You do realize there's a drastic difference between basic target practice/gun care and being in a dangerous situation, right? Newbie hunters typically get the shakes simply from aiming at a deer for the first time. Adrenaline, darkened environments, distracting noises, a panicked crowd, smoke, getting shot at, a target with body armor. Swat teams and soldiers spend years of constant training for those kinds of situations. Having a gun license doesn't turn you into rambo. And playing rambo is precisely the kind of thing that can get someone killed.
I have to agree with this. As much as I support CCW and Stand Your Ground, this is not the average situation for a civilian to handle. The only exception I would give is IF AND ONLY IF a weapon holder happened to be:
1. Positioned perfectly in such a way that he had a clear shot of the killer with no innocents anywhere near the line of fire.
2. Had sufficient control over himself so he would be capable of taking the shot.
Police, swat, and soldiers train a hell of a lot for situations like these and none of it fully prepares you for the fear that strikes you the first time you hear a round buzz by you. Add in the tear gas, a darkened setting, and hundreds of people panicking and anyone will find themselves experiencing the fog of war.
Now if an experienced police officer or combat veteran happened to be in there with a weapon, maybe things would have been stopped quickly. Either way, it's not a good case to use for or against gun control.