An egg probably does not deserve of losing teeth, unless he got it in the eye or something, then its fair I guess you could say, being that he could have been blinded etc
I've had someone shoot a paintball inside my car on the freeway, and I dont know if they were aiming for my face or just my inside windshield, either way they could have caused death(s) by accident, so I would not have felt guilty for breaking thier rear end loose, other than again possibly causing harm to others.