this never happened to me and probably will never happen. still, it is probably not a good idea to get between the business of two total strangers in street: 1. if you win, there is a chance the victim and attacker knows each other and you just put yourself in the middle of some ongoing drama for no reason. 2. if you lose you may end up dead, injured, crippled, robbed. 3. you may end up using too much force and face justice yourself for manslaughter/excessive force. 4. you may get cancelled.   also this.
Turkey