This could go badly for the shooter.
depends on the word "threatened". The suspects were in a carjacked vehicle. This indicates a level of lawlessness which presages violence. However the escalation from diapers to gunshot is a long stretch which probably could have been precluded unless "defense of others" comes into play.
Yes...and forgive me if I'm saying the same as you did in the last line, but the initial threat was not to HIM directly. He made a decision to step in to assist an employee who I suspect was doing their job. Whether or not they were security or not isn't certain at this time. I don't think we can compare this incident with the one several weeks back where a passerby assisted a police officer that was in grave danger and requested assistance.