There's a backstory to this that everyone here isn't seeing. Aint it Cool news had someone on the set who saw the whole thing.
Apparently this guy was notorious for messing with the lights when actors are filming. So Bale asked repeatedly that no one is to mess with the lights or walk into the scene, especially a very emotional scene. Well, this guy not only didn't listen, but seemed to provoke Bale into it.
http://www.aintitcool.com/node/39984
I'm with Bale on this one. I've personally seen crew members lacking disregard for actors and actresses, especially in key scenes.