                              In the

    United States Court of Appeals
                For the Seventh Circuit
                    ____________________
No. 19-2129
UNITED STATES OF AMERICA,
                                                  Plaintiff-Appellee,
                                v.

SEVON E. THOMAS,
                                              Defendant-Appellant.
                    ____________________

        Appeal from the United States District Court for the
        Southern District of Indiana, New Albany Division.
           No. 4:17-cr-13 — Tanya Walton Pratt, Judge.
                    ____________________

     ARGUED JUNE 1, 2020 — DECIDED AUGUST 14, 2020
                ____________________

   Before RIPPLE, WOOD, and SCUDDER, Circuit Judges.
   SCUDDER, Circuit Judge. Sevon Thomas found himself
charged with possessing a ﬁrearm in connection with a drug
traﬃcking crime after he agreed to sell methamphetamine to
a government cooperator. Once Thomas drove to the prear-
ranged delivery time and place, the police arrested him and
searched his car. When police opened the glove compartment,
out fell two ﬁrearms and a bag of methamphetamine. At trial
Thomas claimed that he used the guns for lawful purposes
2                                                 No. 19-2129

unrelated to drug dealing and therefore did not possess them
“in furtherance of” a drug traﬃcking crime in violation of 18
U.S.C. § 924(c)(1)(A)(i). A jury disagreed and found Thomas
guilty. On appeal Thomas argues that the district court made
two errors at trial: improperly admitting so-called “dual-role”
(both expert and lay) testimony from a federal agent and bun-
gling the jury instructions. But Thomas raised neither chal-
lenge below, so he had to show a plain error necessitating re-
versal of his conviction. He falls short, so we aﬃrm.
                               I
    Sevon Thomas came to the attention of law enforcement
through a government informant. At the police’s direction,
the informant called and ordered several ounces of metham-
phetamine from a source known as “Eric.” After arranging for
delivery, the informant told law enforcement that Eric would
bring the drugs to a McDonald’s in Georgetown, Indiana, in
a black Chevy Impala with Kentucky plates. Sure enough, the
delivery took place as planned, and the driver turned out to
be Sevon Thomas. The police arrested Thomas and searched
his car. When a detective opened the glove compartment, 160
grams of methamphetamine and two guns fell out.
    A grand jury charged Thomas with possessing with the
intent to distribute methamphetamine (21 U.S.C. § 841(a)(1) –
Count 1) and possessing a ﬁrearm in connection with a drug
traﬃcking crime (18 U.S.C. § 924(c)(1)(A)(i) – Count 2).
Thomas proceeded to a jury trial, where he admitted that the
drugs and guns were his. He urged acquittal on the ﬁrearm
charge on the basis that he possessed the guns for the lawful
purpose of personal protection and thus not in connection
with his peddling of methamphetamine as required for con-
viction. See 18 U.S.C. § 924(c)(1)(A)(i). Seeking to refute any
No. 19-2129                                                   3

nexus between the guns and the drugs, Thomas and his girl-
friend both testiﬁed that he had a concealed carry permit. His
girlfriend added that he stored the guns in his car to keep
them out of the house and away from their two children.
    For its part, the government attempted to prove that
Thomas had the guns to further his drug dealing by introduc-
ing the testimony of FBI Special Agent Paul Meyer. The gov-
ernment seemed to call Meyer as a lay witness, not an expert.
Yet on direct examination Meyer nevertheless drew on his
training and experience to oﬀer expert testimony in the form
of an opinion about the connection between gun possession
and drug dealing. Meyer told the jury that “a ﬁrearm is a tool
of the drug trade” that drug dealers use “for personal protec-
tion against others in that particular business, whether it’s to
protect the drug proceeds that they may have on them or a
combination of drug proceeds or drugs, the supply of drugs
that they may be dealing at the time.” He added that a gun
could also be used “for intimidation” because a customer who
knows a drug dealer is armed “may be more apt to pay his
bill.”
   The government then questioned Meyer about his
knowledge of Thomas’s case, most of which he had learned
from the agent who searched Thomas’s car:
   Q: And in this case, were there ﬁrearms found?
   A: Yes, ma’am, there was.
   Q: Okay. Were they—were the ﬁrearms found in a locked
case?
   A: No, they were not.
4                                                    No. 19-2129

  Q: Where were the ﬁrearms found in relation to the meth-
amphetamine?
   A: They were co-located with the methamphetamine. As
reported to me, they had been in the glove box. However,
when the glove box fell open, they had fallen on the passenger
side ﬂoorboard area.
    Q: And were both ﬁrearms loaded?
    A: They were.
  Thomas never objected to any aspect of Meyer’s testi-
mony.
   During closing arguments, the prosecutor relied on
Meyer’s testimony to establish a connection between the guns
and the drugs. She argued to the jury that Thomas had guns
“[b]ecause he’s a drug dealer.” She then added, “You heard
from Special Agent Meyer that drugs and guns go hand in
hand and they’re dangerous. Where does the defendant do his
drug deals? Not at his house. He does them at his car.”
   After closing arguments, the district court turned to the
jury instructions. A superseding indictment had charged
Thomas with violating 18 U.S.C. § 924(c)(1)(A)(i), which im-
poses a ﬁve-year minimum sentence on “any person who,
during and in relation to any crime of violence or drug traf-
ﬁcking crime . . . uses or carries a ﬁrearm, or who, in further-
ance of any such crime, possesses a ﬁrearm.” By its terms,
then, § 924(c)(1)(A)(i) can be violated in three ways: by (1) pos-
sessing a ﬁrearm in furtherance of a drug traﬃcking crime, or
by (2) using or (3) carrying a ﬁrearm during and in relation to
such a crime. See United States v. Haynes, 582 F.3d 686, 704 (7th
Cir. 2009) (abrogated on other grounds).
No. 19-2129                                                    5

    At trial the government sought to prove the § 924(c) count
by focusing on only the ﬁrst way of violating the statute—by
showing that Thomas “possesse[d]” the guns “in furtherance
of” a drug crime. The trial court so instructed the jury, ex-
plaining that a conviction on Count 2 required ﬁnding beyond
a reasonable doubt that Thomas (1) possessed methampheta-
mine with the intent to distribute it, and (2) knowingly pos-
sessed a ﬁrearm (3) in furtherance of the methamphetamine
possession. In conveying this instruction, the district court did
not deﬁne or otherwise explain what it meant for the gun pos-
session to be “in furtherance of” possession of the metham-
phetamine. But the district court did deﬁne “carry,” “during,”
and “in relation to”—terms Congress used in parts of § 924(c)
but that were not any part of the government’s approach to
proving Count 2. Here, too, Thomas lodged no objection.
    The jury returned guilty verdicts on Counts 1 and 2, and
the district court sentenced Thomas to a total of 15 years’ im-
prisonment—ten years for the drug charge plus ﬁve consecu-
tive years for the ﬁrearm oﬀense.
    On appeal Thomas contends that the district court failed
to follow the correct procedures for admitting Special Agent
Meyer’s testimony because it included both expert and lay
opinions and thus amounted to “dual-role” testimony.
Thomas also argues that the jury instructions confused and
misled the jury by omitting any deﬁnition of the statutory “in
furtherance of” requirement but including deﬁnitions of stat-
utory terms not relevant to the precise § 924(c) charge in
Count 2. Together, Thomas says, these errors warrant reversal
of his conviction on the Count 2 § 924(c) gun oﬀense.
6                                                    No. 19-2129

                               II
    We start with the admission of FBI Special Agent Paul
Meyer’s testimony. Ordinarily we review a district court’s de-
cision to admit testimony for an abuse of discretion. See
United States v. Parkhurst, 865 F.3d 509, 514 (7th Cir. 2017). We
apply a more deferential standard here, though, because
Thomas never objected to Meyer’s testimony during trial. In
these circumstances, Thomas needs to show that the admis-
sion of the testimony amounted to plain error—an error so
profound that it compromised Thomas’s substantial rights
and seriously aﬀected the fairness, integrity, or public reputa-
tion of judicial proceedings. See United States v. Olano, 507 U.S.
725, 736 (1993); see also United States v. Resnick, 823 F.3d 888,
896 (7th Cir. 2016) (applying the same standard).
    Thomas focuses on the diﬀerence between lay and expert
testimony. “[L]ay testimony results from a process of reason-
ing familiar in everyday life, while expert testimony results
from a process of reasoning which can be mastered only by
specialists in the ﬁeld.” FED. R. EVID. 701 advisory committee
note on 2000 amendments (internal quotations omitted). Lay
testimony may be admitted if it is based on personal
knowledge and helpful to determining a fact in question. See
FED. R. EVID. 701. Meanwhile, to admit expert testimony, a
district court must ﬁrst ensure that the witness is qualiﬁed to
oﬀer the opinion at issue. See FED. R. EVID. 702. A district court
should admit expert testimony only if it will help the fact-
ﬁnder understand the evidence, ﬁnds support in suﬃcient
facts or data, and reﬂects the product of reliable methods or
principles, reliably applied to the facts of the case. See id.
  Sometimes a witness oﬀers both lay and expert testi-
mony—what the case law calls “dual-role” testimony. See
No. 19-2129                                                     7

United States v. Jett, 908 F.3d 252, 267 (7th Cir. 2018). Imagine
an engineer who testiﬁes in a products liability case. The en-
gineer may give lay testimony from ﬁrsthand involvement
designing a consumer product—say, a lawn mower—alleged
to be defective. The same engineer may also be qualiﬁed to
give an expert opinion about the design of a competitor’s
product—for example, testimony about the alternative design
of the shutoﬀ handle on a competitor’s mower.
    The setting here is law enforcement. All agree that Special
Agent Meyer provided both lay and expert testimony at
Thomas’s trial. Meyer testiﬁed that, “[a]s reported to [him],”
the ﬁrearms found in Thomas’s car were loaded and “co-lo-
cated with the methamphetamine”—lay testimony based not
on his specialized knowledge but instead on his personal fa-
miliarity with the case. Earlier in the questioning, though, the
government asked Meyer to oﬀer a view “[b]ased upon [his]
training and experience” about the connection between gun
possession and drug dealing. He replied that ﬁrearms are
“tool[s] of the drug trade” used “for personal protection” and
“intimidation.” This description ﬁts squarely within the type
of specialized knowledge—in this case rooted in a law en-
forcement oﬃcer’s experience investigating drug oﬀenses
over many years—that Federal Rule of Evidence 702 consid-
ers expert testimony.
   Our case law emphasizes the care district courts must take
in admitting dual-role testimony. We most recently under-
scored the point in United States v. Jett, explaining that the ad-
mission of dual-role testimony, while permissible, risks con-
fusing the jury. See 908 F.3d at 267 (collecting cases). More
concretely, a jury “may unduly credit the [case agent’s] opin-
ion testimony due to a perception that the expert was privy to
8                                                   No. 19-2129

facts about the defendant not presented at trial” or “may be
smitten by an expert’s aura of special reliability.” See id. (in-
ternal quotations omitted). And where the oﬃcer provides ex-
pert testimony about criminal methods, as Special Agent
Meyer did here, juries should be cautioned “that the opinion
is based on the expert’s knowledge of common criminal prac-
tices, and not on some special knowledge of the defendant’s
mental processes.” United States v. Lipscomb, 14 F.3d 1236, 1242
(7th Cir. 1994).
     Sound trial procedure helps mitigate these risks. Fore-
most, the district court should “encourage the government to
present the expert and lay testimony separately” because the
risk of confusion is greater for “[a] witness who careens from
one type of testimony to the other.” Jett, 908 F.3d at 269. When
the expert portion of an agent’s testimony begins, the court
should “allow the government to lay its foundation and es-
tablish the agent’s qualiﬁcations,” then “instruct the jury that
the testimony it is about to hear is the witness’s opinion based
on training and experience, not ﬁrsthand knowledge, and that
it is for the jury to determine how much weight, if any, to give
that opinion.” Id. at 269–70.
   Here the district court did not follow the procedures we
outlined in Jett. That almost certainly happened because the
government failed to adhere to its obligation to identify
Meyer as an expert in advance of trial. See FED. R. CRIM. P.
16(a)(1)(G). Nor did the district court take aﬃrmative steps to
vet Meyer’s qualiﬁcations and opinion once it was clear that
he would oﬀer expert testimony. See Gopalratnam v. Hewlett-
Packard Co., 877 F.3d 771, 779 (7th Cir. 2017) (explaining that
before admitting expert testimony the district court “must de-
termine whether the witness is qualiﬁed” (internal quotations
No. 19-2129                                                   9

omitted)); see also FED. R. EVID. 702 (describing an expert wit-
ness as one qualiﬁed “by knowledge, skill, experience, train-
ing, or education”). We have consistently emphasized that the
district court must fulﬁll this gatekeeping responsibility. See
United States v. Tingle, 880 F.3d 850, 854 (7th Cir. 2018).
Equally important is the district court’s duty to limit the risk
of jury confusion when admitting dual-role testimony. See
Jett, 908 F.3d at 269–70.
    But the district court’s error in Thomas’s trial was not
plain and so does not warrant reversal. Had the government
disclosed and oﬀered Special Agent Meyer as an expert, his
testimony would have been unobjectionable. Meyer testiﬁed
that he had 23 years’ experience in law enforcement, includ-
ing with ﬁrearms and drug traﬃcking crimes. He had the req-
uisite qualiﬁcations to inform the jury, based on his training
and experience, how and why drug dealers often possess and
use ﬁrearms. It is well-established that such testimony falls
into the category of specialized knowledge (and thus expert
opinion) and can help a jury determine whether a defendant
like Thomas possessed a gun in furtherance of a drug crime.
See United States v. Blount, 502 F.3d 674, 680 (7th Cir. 2007)
(“The average juror does not know how a drug business is
run, and to that extent [a law enforcement expert’s] testimony
was useful in showing the link between crack and guns.” (in-
ternal citations omitted)).
   Even setting aside Meyer’s testimony, the government had
ample evidence to show that Thomas was using the ﬁrearms
found in his car to facilitate his drug dealing. Detective Ste-
phen Coleman testiﬁed at trial and explained the search he
conducted of Thomas’s car. He described opening the glove
compartment only to see two guns and a signiﬁcant amount
10                                                   No. 19-2129

of methamphetamine fall out. On these facts we have little dif-
ﬁculty seeing how the gun possession could have furthered
Thomas’s drug dealing: the guns and drugs were stored to-
gether and both were within arm’s reach of the driver—
Thomas—who had driven to a pre-arranged location to de-
liver methamphetamine.
    We reached a similar conclusion in Jett, even though our
review there was merely for an abuse of discretion. See 908
F.3d at 265. The district court did not follow the proper pro-
cedures for admitting dual-role testimony, but we neverthe-
less held that the error was harmless given the strength of the
government’s case. See id. at 270.
    We follow suit here. Not only was the evidence against
Thomas substantial, but he bears the more demanding bur-
den of showing plain error to boot. On the evidence presented
at trial, we cannot say that the district court’s handling of Spe-
cial Agent Meyer’s dual-role testimony amounted to plain er-
ror under the demanding standard the Supreme Court an-
nounced in Olano. See 507 U.S. at 736.
                               III
    Thomas next challenges the jury instructions on Count 2.
In the ordinary course we review a district court’s decision to
give a jury instruction for an abuse of discretion, reversing
“only if the instructions, taken as a whole, misled the jury.”
United States v. Erramilli, 788 F.3d 723, 730 (7th Cir. 2015).
   Again, Thomas did not raise his challenge below. Quite
the contrary. His counsel told the district judge that he had
“no objection” to the jury instructions, raising the question
whether Thomas altogether waived appellate review. See
United States v. Johnson, 874 F.3d 990, 1000 (7th Cir. 2017)
No. 19-2129                                                     11

(explaining that traditionally “approval of a jury instruction
in the district court extinguishe[d] any right to appellate re-
view of the instruction”). In recent decisions, however, we
have “recognize[d] the harshness of waiver” in the context of
challenges to jury instructions and “hesitate[d] to determine
blanket approvals ‘knowing and intentional decision[s]’”
where counsel merely engaged in a “rote call-and-response
colloquy with the district judge.” Id. Here we assume that
Thomas only forfeited his challenge to the jury instructions
and therefore review them for plain error. See id. at 1001.
    Thomas contends that the jury instructions wrongly con-
ﬂated multiple provisions within 18 U.S.C. § 924(c)(1)(A)(i).
Recall that the indictment charged Thomas with violating
§ 924(c)(1)(A)(i), which makes it a crime for someone to (1)
possess a ﬁrearm in furtherance of a drug traﬃcking crime, or
to (2) use or (3) carry it during and in relation to the crime. See
Haynes, 582 F.3d at 704. The government urged the jury to ﬁnd
Thomas guilty only if he violated the statute the ﬁrst way—if
his “possession of the ﬁrearm was in furtherance of the pos-
session with the intent to distribute methamphetamine.” To
obtain a § 924(c)(1)(A)(i) conviction based on possession, the
government had to “present a viable theory as to how the gun
furthered the drug possession or distribution (e.g., being
available to protect the drugs or drug dealer)” and “present
speciﬁc, non-theoretical evidence to tie that gun and the drug
crime together under that theory.” United States v. Castillo, 406
F.3d 806, 815 (7th Cir. 2005).
   Thomas underscores that the jury received no instruction
on what it meant to the possess a gun “in furtherance of” a
drug oﬀense—a statutory requirement mandating the show-
ing of a “critical nexus between the particular gun at issue and
12                                                  No. 19-2129

the drug traﬃcking oﬀense; a nexus that . . . serves to elimi-
nate the possibility of a conviction for innocent possession of
a gun, such as when a gun is merely present at a crime scene.”
Id. at 820 (emphasis omitted). In the same vein, Thomas says
the instructions unnecessarily deﬁned the word “carry.” He
insists that this deﬁnition was especially prejudicial because
it said that a person can “carry” a gun even if it is in a con-
tainer “such as a glove compartment”—exactly the place
Thomas’s guns were found. Finally, Thomas quibbles with
the fact that the jury was given deﬁnitions for “during” and
“in relation to.” Like “carry,” those terms are relevant to other
ways of violating § 924(c)(1)(A)(i), but not to the exact charge
alleged in Count 2—possessing a ﬁrearm in furtherance of a
drug crime. Taken together, Thomas says, these ﬂaws in the
jury instructions amounted to plain error.
   Imperfect as they were, the jury instructions were not so
confusing or misleading as to warrant reversal under plain er-
ror review. To be sure, we agree that the more prudent ap-
proach is to include some elaboration on the meaning of the
phrase “in furtherance of.” Better yet, the district court could
have drawn on our court’s pattern jury instructions, which ex-
pressly “recommend[] that courts instruct jurors on the mean-
ing of ‘in furtherance of’ a crime of violence or drug traﬃck-
ing crime.” PATTERN CRIMINAL JURY INSTRUCTIONS OF THE
SEVENTH CIRCUIT at 242 (2012 ed.).
    Still, we cannot say that leaving out the deﬁnition compro-
mised Thomas’s substantial rights. We observed in Castillo
that the phrase “in furtherance of” has a plain meaning that
“naturally and necessarily connotes more than mere presence
or innocent possession; as its natural meaning suggests . . . it
requires that the gun be possessed to further, advance or help
No. 19-2129                                                   13

forward the drug crime.” 406 F.3d at 821 (emphasis omitted).
Put diﬀerently, it was not reversible error to fail to deﬁne the
phrase “in furtherance of” because its apparent meaning
“render[s] any deﬁnitional instruction perhaps helpful but
not necessary.” United States v. Morris, 576 F.3d 661, 673 (7th
Cir. 2009). Omitting that deﬁnition here was not plain error.
    Nor was the district court’s choice to deﬁne the terms
“during” and “in relation to.” In United States v. Harvey, 484
F.3d 453 (7th Cir. 2007), we concluded that although an indict-
ment was defective because it replaced “in furtherance of”
with “in relation to,” the error did not warrant reversal be-
cause those phrases “are close enough in meaning that [the
defendant] knew the essence of the charges he was facing”
when he opted to plead guilty. Id. at 457. Our reasoning fol-
lows a similar path here: the jury was instructed to ﬁnd
Thomas guilty if he possessed a ﬁrearm “in furtherance of”
the drug crime, a phrase with a readily understandable con-
notation. We cannot conclude that the superﬂuous inclusion
of deﬁnitions for “during” and “in relation to”—terms with a
similar signiﬁcance to “in furtherance of”—distracted the jury
from its task to determine whether Thomas used the guns to
advance his drug dealing.
    Even where a jury instruction altogether omits an element
of a crime, we decline to reverse under plain error review if
the jury heard overwhelming evidence proving that element.
See United States v. Maez, 960 F.3d 949, 964 (7th Cir. 2020). Not
only was the error here less grave, but the state’s case was
strong. The jury heard unmistakable evidence showing a con-
nection between the guns recovered from Thomas’s car and
the methamphetamine he planned to deliver to the govern-
ment informant—the two guns and drugs literally fell out of
14                                                 No. 19-2129

the glove box together. The factors we use to distinguish be-
tween mere possession of a gun and possession in furtherance
of a drug crime include the time and circumstances under
which the gun is found, the proximity of the gun to the drugs
or drug proﬁts, the accessibility of the gun to the defendant,
and whether the gun was loaded, among others. See United
States v. Seymour, 519 F.3d 700, 715 (7th Cir. 2008). With its
burden framed this way, the government had suﬃcient, if not
sureﬁre, proof that Thomas was using guns to enable his drug
dealing: he arrived with the methamphetamine at exactly the
time and place the informant said he would, the drugs and
guns were located together, all the contraband was within
Thomas’s reach, and the guns were loaded. The jury had am-
ple evidence to conclude that Thomas possessed the ﬁrearms
to further a drug crime.
                              IV
    Finally, Thomas urges us to consider the dual-role testi-
mony and the jury instructions in combination. In assessing
whether a conviction should be upheld despite two or more
mistakes made at trial, we assess cumulative error, or “the
harm done by the errors considered in the aggregate.” United
States v. Santos, 201 F.3d 953, 965 (7th Cir. 2000). To show cu-
mulative error, Thomas had to establish that “considered to-
gether along with the entire record, the multiple errors so in-
fected the jury’s deliberation that they denied [him] a funda-
mentally fair trial.” United States v. Groce, 891 F.3d 260, 271
(7th Cir. 2018).
    Whether we consider them individually or together, the
errors at Thomas’s trial do not undermine his ﬁrearm convic-
tion. The jury had more than enough evidence to ﬁnd beyond
No. 19-2129                                          15

a reasonable doubt that Thomas possessed the two guns in
furtherance of his sale of methamphetamine.
   Accordingly, we AFFIRM.
