What would YOU do if someone attacked the person you had
feelings for?

In this circumstance I would do anything but knock her out.

        That's the point which invalidates the rest of your
current argument.  He did not intend to KO her.  What did he do?  He
kicked the bonbori, broke the ball, but never anticipated it hitting Shampoo
on the head.  If he wanted to KO Shampoo, she would have
a foot-shaped bruise on her face.