That was along the lines of the reaction he'd expected from Harley.
And then her gun went off.
The whole situation was becoming increasingly unsafe. For him and everybody else around. He wasn't sure that he could save the butterflies from Harley now that they had her attention. And he was fairly sure that she wouldn't need saving from them any time soon.
So that just left him.
He needed saving from the whole lot of them. Somebody was going to accidentally shoot him in the face, or else they were going to try to pick a fight with him to get him back to the Joker.
The easiest solution was to leave.
With nothing more than a whistle of air, Bruce released his zipline. It shot across the street and embedded into the side of a building. The trigger pulled, it tore him out of the situation.