The Stoics say that it is a logical mistake to believe you can control something you cannot. So we are necessarily working outside of the laws of man as we enter into the exploration of this question. The first step in assessing whether or not you should respond violently to a situation, at least in my opinion, is to ask yourself if you are trying to control something outside of your control. Are they hitting you for no reason? Are they just violent animals looking to do harm because they are a vicious person? And if it is, well, then in this case, you're very likely obligated as a moral actor to intervene in this dispreferred outcome.