So you do not feel you have an obligation to protect someone other than "you and yours"?
my law enforcement training would more than likely, and unless my children were with me I would act. Should the average private citizen do something... That a gut check they will have to make in that moment. But, it is not trying to play police to act in a lethal force incident, it's an individual making a measured response to a situation. Would you pass by a fresh horrible accident on the roadway because you do not want to be an EMT? (Failure to stop and render aid?)
The "Good Samaritan Law" covers me if I help an accident victim. I am not going to spend the next decade getting pounded in the ass because I wanted to play cops and robbers.
I would most likely help someone in danger but I am not holding anyone.