Maybe he'd been bothering her for a while, and not taking her rejections. In which case, she probably did the right thing.
If this was his first time making his move, and she did that, then it's cold-blooded.
Still, you don't do the big, showy bs to woo a girl. That's simping, as others have pointed out, and you have to be ready to have your heart shattered in that event. He learned a valuable lesson there. Hopefully it doesn't turn him into a deviant or something. PEACE.