And duty? Having a concealed carry permit, as a civilian, doesn't give you any duties, per se. It gives you lots of responsibilities to be lived up to, chief among them realizing you are not a LEO.
If a cop has to be careful interceding in a fight, you have to be 10 times as careful. In fact, you should just call 911 and let them handle it. Unless you're a cop, you are not a cop.