That would be fkd up if he got in trouble for that; but the way the legal system is, who knows. If they say he had the opportunity to escape the situation, but didn't, he would be in some doo-doo. Especially if the pimp claimed he suffered terribly because of this and managed to get a little sympathy. Also, I think pimps hands were down, eliminating the opportunity to say that he was attacked or was about to be, and was afraid.
If he's a black belt he might be in trouble. I saw a case a long time ago about a martial artist that worked as a Ninja Turtle at the mall, and was taunted and harassed after talking to a girl that some other guy liked. He turned around and kicked the guy, who fell, hit his head, and (I think) died. The prosecution made him look pretty bad, just for defending himself. The system is haywire.