Like most everyone, I was shocked and disgusted by the shootings in Aurora, Colorado. There have been, and will be, many blog posts regarding it. But I wish to address one viewpoint that arises almost every time some horrific event like this happens. Invariably, someone will say that if there had been an "armed citizen" present, the matter would have been over quickly, with many lives saved. This is usually coupled with arguments that private citizens should be allowed to carry concealed weapons. There is a certain percentage of fandom that holds to this view, and I have run into several of them.
Some background. I have owned and carried firearms most of my adult life. I am trained, qualified, and licensed to carry sidearms ranging from 9mm to .45 Auto, and everything in between. I have carried and fired almost everything from shotguns, rifles, and submachine guns to assault rifles. Real ones, not the junk marketed as "assault rifles" at the local gun store. I have been present at situations where gunfire was exchanged, and while I have been fortunate enough never to have shot and killed anyone, I have helped take down armed and dangerous felons and have come very close to shooting some of them. I own several firearms, and unless I am being paid to carry one, they are not taken out of storage unless I am going to the range to practice. My sidearms are not a political or fashion statement.
People who like to fantasize about what they would have done if they had been there with a gun have no idea what a real gunfight is like.
First, consider the site. In Aurora Colorado it was a darkened movie theater. A psycho suddenly appeared and begins firing. Disconcerting. Then there are the sounds. What you hear on TV and movies are blanks. Live ammo can literally be deafening, and the side blast can shatter windows. In seconds you have a screaming, panic-stricken mob scrambling to escape. Theaters are cramped, with as many seats as the local safety ordinances will allow. People are running along narrow spaces, climbing over seats, and falling down all over each other while a gunman is shooting them down. The floor slopes down to the screen, and blood is slippery, which only adds to the confusion as people slip and fall. In addition there are the sounds and light from the movie to add to the confusion.
Somehow, in the middle of the jostling mob you manage to draw your sidearm. Somehow you manage to spot and identify the gunman. Somehow, in the middle of the screaming, panicked mob, you have a clear line of fire.
Note, if you should happen to shoot anyone else, no one will cut you any slack. Not the police, DA, Courts, the public, nor the media. A zebra being torn apart by hyenas will be having a better day. And things will get worse.
The families of the injured and dead will want blood. If they can't get it they will go for everything else. All you own or will ever have is up for grabs. Lawsuits are no fun. Trust me. If you should injure or kill an innocent civilian, you can kiss the rest of your life goodbye.
But let's say you get a momentary clear line of fire. Oops, he's wearing body armor. While most body armor will stop most pistol rounds, the impact will hurt. So now you have a pissed-off psycho with an assault rifle. So you try for a head shot.
I am a better than average shooter. Not just my opinion, my test scores on my twice-yearly requalifications placed me in the top five percentile. On the range, in good light, with a stationary target, I can consistently expect to make a head shot at fifteen meters. In a darkened theater, with a moving target who is shooting back at me, in the middle of a screaming, panic-stricken mob? I would not bet my life on it, or anyone else's.
Also, what if there is another "armed citizen" in the theater? He draws his sidearm. How do you both know you're on the same side? Things could get very ugly very quickly.
Also, theaters are big buildings, and are usually made with lots of reinforced concrete. A 9mm leaves the muzzle at over 1300 ft/sec, a .45 at about 1000 ft/sec. You cannot control potential ricochets.
But maybe you're the only armed one there, and by some weird, and very fortunate, concatenation of events, you manage to get the drop on him and fire off a shot that scores. At that moment the local SWAT team rushes in armed and ready, adrenaline flooding through their bloodstream, to find you standing amidst a hellish scene with a smoking gun in your hand. Guess what happens next.
My feeling is that you should keep your fantasies about gunfights in your daydreams, or put them into your novel about Penelope Courage, Girl Secret Agent. If you should ever be so unlucky as to be caught in such a situation, Get The Hell Out of There, and to a safe place. Take out your cell phone and try to give the police the clearest, calmest description of what is happening. They will appreciate the intel. Leave the gunplay to the professionals with the weapons, the gear, the training, and the experience.
If you really want to play with assault rifles and such, join the military or the police. They'll give you the training, the gun, and the paperwork that says you can carry and use them. It's not as much fun as you may think.