For a wild second, Kevin thought she was going to fall out the window without him even touching her. What if she fell to her death? He'd have to call the Muggle police, and then maybe they'd suspect him of murder! That couldn't happen. He'd have to move quickly to be the movie-type hero that kept the villain from falling to their deaths so that they would see the right kind of justice during their lifetimes.
And then, as he was taking a step forward, the hand that had been on his wand starting to reach out to grab hold of her, she said his name. It wasn't until then that he realized she was familiar, that he knew her.
"Holy shit, Su!" he said aloud, eyes widening. "Is it really - what are you doing here?"