Many carry, but many are not properly trained in these circumstances. You shoot, you miss, you hit an innocent. How many are qualified at 20, 30, 40 yards? Then you have average citizen completely outgunned. Also, you don't know if a second shooter is following the initial shooter. You just can't get a permit, buy a slick looking Sig, holster up, tell all your friends, dream of what you would do, then reckoning day comes. Do you try and escort as many shoppers as possible out of harms way or do you try the Navy Seal route? Not an easy answer until it happens to one of us. Get yourself trained and get the proper carry weapon. Learn how to use it, inside and out and get trained.