So like a fool, I started looking for his (nonexistent) lens. It took me a few moments to realize that this fifth youth was a plant, meant to distract anyone who came across the mugging.
That's when I called the police. Would I have done things a bit differently, in hindsight? Probably. But in situations like this one, you don't have a whole lot of time to realize exactly what's going on.
This was a big city he was in, according to his tale.
Why would you presume that anyone rescued from being a victim of a crime by a stranger willing to use deadly force on their behalf would be appreciative?
Heck, try to imagine that you pull a gun on some ruffians intent on robbing some pinch-faced woman who just happens to be the president and CEO of the 'National Coalition To Ban Handguns'? Think she's going to back up your story in front of the police? Why, it was that cowboy (you) with his gun that actually *escalated* the violence, she'd be obligated to say.
Your CCW license is not license to pretend you're Spiderman. In fact, Spiderman got in all sorts of legal trouble for his deeds, usually thanks to that liberal-assed narcissist newspaper editor J. Jonah Jameson that he worked for down at the Daily Bugle.