Generally yes, but it would depend on whether he was still a threat to you or anyone else at the time you you shot him. Don’t forget, he just shot someone which is pretty good evidence he’s a threat. I can’t think of a locale where you can’t defend others.
I guess if you missed the target, then the threat is not direct. No?
New Jersey. Because if you are carrying here you are 95% probable to be in violation already. It is a may issue state, but good luck getting a permit.
Apparently you’ve never been to Massachusetts.