I think after reading this thread, I'm more cognizant that other CCWers around me might be having to react to imminent threats that they perceive, so I shouldn't automaticly slap steel and start gunning at them myself. Slap steel and take cover, yes, but wait to see what else the shooter is about to do. Continuing to gun down restaurant patrons or shouting a demand for valuables makes it pretty clear, he's a BG and I have to end him, if I can. Holstering his gun and telling people to call 911, he's prolly a GG like me, and if I were to shoot him, I'd be committing a crime.
First thing, after slapping steel and taking immediate cover because of shots fired in public would be to usher my compatriots out of the danger zone, bills be damned, the meal is over at that point. After that is aquiring targets and covering our escape. Anything that looks like it might be a shooter attempting to stop us from leaving, must be a BG of some kind, and he dies.
After mine are out of the danger zone, I would stay behind if I saw any kind of imminent threat, but if everyone else was still apparently safe and healthy, I'd just assume that those people are lacking in the same self-preservation instinct me and mine possess or else, there really is no danger of imminent death by firearm.
If, after mine were safely away and I was bringing up the rear, there was a commotion going on, I'd prolly be busy trying to (re)acquire a target, the source of the gun shots and ushering those closest to my (physicly, not emotionally) to flee as mine already had. If at any time someone pointed a gun at me, sorry to say, at that point, I'd prolly have to pull the trigger.
Rather be judged by 12 than carried by 6, and if you knew how big I was, you'd sympathize with those 6.