I know you live on the liberal side of the US, but here, you are allowed to protect other people, whether or not you even know them. If a bad guy seems to be about to harm someone, you can shoot them.
I mean I spent most of my life in a place with open-carry allowed, and stopped requiring handgun registrations altogether. The only thing left was the CCW requirement for concealed-carry, but I am well-versed in firearms, and have owned a ton of them.
Just because you can shoot someone doesn't mean it is a good idea. But if you have the epic hero fantasy you want to roll with then by all means go ahead tie up the next many years of your life with the legal repercussions that come along with that scenario, since you will likely have to go through a police investigation at minimum and potentially defend yourself from criminal charges. And don't forget civil suits from the family of the person you shot. You may walk away from that without a scratch so your priorities are you own.