VFX artists have been posting their work from Justice League, some of it which wasn’t in the movie, but recently a VFX reel for Suicide Squad popped up as well. It features deleted footage from the scene between Batman and Harley Quinn after he rescues her from the under water car crash.
The Suicide Squad novel actually included this scene. In the book, Harley Quinn asks “Why the favor, Bats?”, to which Batman replies: “Joker took something important away from me. It’s my turn.” That’s a clear reference to Robin, who was killed by the hands of The Joker. In the video above at the 20 second mark, you can tell that Ben Affleck is saying a variation of that line.
If you’ve read the Suicide Squad novel you know it includes a lot of things that didn’t make it into the theatrical cut of the movie. There’s more Joker and he’s much more abusive to Harley Quinn than he was in the movie as well. Warner Bros. reportedly hired a trailer company to edit Suicide Squad and used reshoots to lighten the tone after the negative response to Batman v Superman.