Yeah, I understand it better now after thinking about it and reading what you and others have said.
Still I'll always think of it as a sad ending. Also I still doubt Leo would have done anything to Chase. Yeah, I get that he was not in his right mind, but he still had reasoning. just before Chase tells him whether or not it's over, Leo calms himself for a moment. Also When Chase tells him it's over, he doesn't react with with rage and start shooting, he does actually seem to let go, even if he's shocked. Now yeah Leo could have been a danger to Chase if he stayed alone with him, but I think the worst he would have done would be holding/hugging Chase too tightly and not letting go of him. Also it seemed to me that the hysteria was already calming down, the gunshots had stopped and there didn't seem to be any more crazy people running around, so I wonder if the worst of Leo's aggression was already past? I could be misunderstanding, as thats my big problem, but I still think there should have been another option.