Fighting Question-Punt to the Jaw?

Hello, just need some help , recently i have been talking to a friend of mine, and he gets in to regular fights in school, and he always says when the opponent is down he runs and punts them in the jaw( a bit like Randy Orton's Punt kick in wwe, except he makes contact to the jaw when he is facing sideways), can this fighting move be fatal for the oppenent??? Caus nowadays people are using this quite often, and it looks quite useful for taking the opponent in one hit, but to clarify can this cause fatal injures?????,this is because in my school my people always get in to fights, and they asked me if it can cause fatal injures?? because we don't want that. So my Question can this maneuver cause fatal injures???