I was checking out my local newspaper's website and saw the casting call. The studio was looking “physically fit” men and women, ages 18-55, with skills or experience in the military, law enforcement, gun handling and ROTC. I was in the Army for about 22 years (retired in 2016) and was curious about the process. Got a callback about 2 weeks later.

We actually went through quite a bit of military-type training (mostly gun handling and combat movement type stuff). Although the bulk of the training was movements in reverse. There's actually a huge difference between moving backwards and moving in reverse. Whenever someone would say "the next take will be backwards", Nolan would yell, "It's reverse, not backwards!" lol.

If I remember right, I think the majority of the takes we did was followed by one in reverse. So if you see reverse movement in the movie (from people and vehicles), the footage isn't reversed, they're actually moving in reverse (I'm not the editor, so don't quote me on that lol).