The thing with Begins was, Bruce said he wouldn't become a killer. Ducard was egging him on to kill him and was mocking Bruce for saving him in the first place. Bruce's reasoning behind it is simple,
"I won't intentionally kill someone in cold blood, but if I leave them to die or kill them accidentally, it's fine"
That really doesn't fit in with the philosophy he has in the comics...Not saving them just because he's the hero, but because he wants to preserve life, like Thomas Wayne did.
That view in Begins makes sense to THAT characterisation of Batman. He won't shoot a criminal to death, but he won't save them if he get's mocked for it, and he doesn't mind if he kills a criminal accidentally, because it wasn't intentional on his part. I'm sure there is a logic in there somewhere, but I can't find it
Superman doing something like that
"I won't kill you, but I don't have to save you"
It isn't him. Batman may not have a problem with leaving someone to die. But it's in Superman's very nature to save lives from anything and everything. He's a more spiritual character, who has an appreciation for life. Superman has more empathy than Batman.
Cause in the comics Batman can be a cold character, he just feels less warmth than Superman in himself. I think that scene in Begins was definitely inspired by Frank Miller's Batman, a very cold and cynical interpretation.