He was protecting Bart. He always would. Even if Bart didn't know him, Tim still cared. Even more infact because he was alive. He refused to live in another world where Bart died. That just wasn't his idea of a party. Bart was his best friend, second to Superboy. This one was different, sure. But still Bart. Tim would still treat him as such until he was told to do otherwise, and even then he probably wouldn't listen..it wasn't bat-behavior to listen to orders like that.
He nodded as he looked up at her and frowned. "Why are mobsters always fat?" A cranky look though it was rhetorical for the most part. He hadh ung several of them off a building. He had no choice in the matter, he was allowed to be a bit cranky. It was Batman's move, not his. But they only understood intimidation by the point Robin had to come out and play.