he grabbed you by the wrist when you were just about to fall off the building. Joker attacked the place where you worked and an explosion just went off, if Nightwing wasn't on time, you'd have fallen and died "Hang on!" he grunted as he pulled you slowly up with one arm while with the other one keeping the both off you from falling, he pulled you back on the roof, in safety. After that he came on the roof back himself, pulling him and then looking concerned at you "Are you alright?"