Some will say that the good guy was a cop and so different than an armed civilian but he was off duty and therefore just another armed citizen.
Originally Posted by JD Barleycorn
Some would say that, but those "some" would be incorrect.
Most states, and I don't know why Minnesota would be any different, have the same "use of force" principles apply to the police as are applied to "citizens" (meaning nonpolice).
Additionally many states have a provision tucked away in their laws relating to public servants that police are not "off duty" in the sense that they are prohibited from exercising their authority as a police officer when they are not "on the clock" so to speak. (That's distinguished from departmental policy.)