The 'Batman v Superman' director made one of the most unexpected scenes in 'Suicide Squad'

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Zack Snyder directs Ben Affleck on the set of "Batman v. Superman: Dawn of Justice."

Warning: This review contains spoilers for "Suicide Squad."

The DC Extended Universe can't quite shake Zack Snyder.

The director earned dismal reviews after March's "Batman v Superman: Dawn of Justice." Yet, he remains an integral part of the cinematic comic book universe. He even left his mark on "Suicide Squad," which was directed by David Ayer.

According to Collider, Snyder directed one key scene in "Suicide Squad." The scene Snyder directed involved a surprise cameo from The Flash (Ezra Miller). The brief flashback shows how Captain Boomerang (Jai Courtney) was captured before joining the team. With his speed, it was The Flash who brought him to justice.

If you think about it, The Flash's appearance makes sense. After all, Captain Boomerang is a Flash villain, as many have pointed out.

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Snyder directed a scene where Captain Boomerang (Jai Courtney) is captured.

The scene was shot in London, where Snyder was busy filming "Justice League" while "Suicide Squad" was in post-production.

"Flash was always in the movie, we just got lucky because 'Justice League' was happening and they had the uniform, they had the assets, so we were able to get that photography," Ayer told Collider.

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The Flash (Ezra Miller) is already a fan favorite.

While the scene might have felt like a tie-in to the upcoming "Justice League" that was thrown in there, Ayer revealed that it was in the script all along. It's a fun moment, and it already feels like The Flash will be one of the standouts of the next phase of the DC Cinematic Universe.

Snyder's involvement is interesting, given that the reshoots that "Suicide Squad" went through seemed to be a tug-of-war between a lighter tone closer to that of Marvel's, and the darker world that Zack Snyder set up during "Man of Steel" and "Batman v. Superman." Even as it looks like "Suicide Squad" is set for a huge opening weekend, these are issues that the DC Extended Universe will have to grapple with for its next few movies.