"you would have tried to help."
Define "try to help". Would that be (1) alerting the store manager and calling security, (2) yelling at the perps to stop, (3)jumping in and pulling the perps off the victim or (4) beating them senseless until they stopped?
You forgot "take notes".
I think we all would use our common sense to decide what we could do to help. For the record, “help” is stopping the beating. First of all, I would be likely to take greater risks to intervene if a female is being beaten. In this situation, physically putting yourself between the victim and the aggressors could stop the attack or at least buy time. But there might be a shot to take down more than one attacker at a time. Especially if you see others willing to help. I can’t imagine seeing something like this and not thinking about my mom or my wife.
I would like to answer your earlier question about the four gangbangers. If it’s obvious that I alone could not physically stop the attack then your method of getting security and noting details is the only help that can be offered. But I would rather taking the beating myself than live with the images of a woman being abused like that.