Bruce isn't going to get out of this alive. He quickly loses count of the number of times the knife sinks into him, and he can't defend himself, not against a man who's been doing this since long before he was born. The worst part is that he doesn't want to hurt Thor, either. He's not in his right mind, and that noise he makes is horrible. He's sick and wounded and Bruce would want to help him if it weren't for the fact that he's currently being murdered.

Then he sees Tony. He doesn't acknowledge him, because then that would draw Thor's attention, but it makes him finally try to actually stab Thor in the chest. He doesn't want to hurt Thor, but he wants Thor to kill Tony even less. He doubts he can do much, but at least he might be able to slow him down.