I would imagine that if you really consider a theater to be a place where you need to bring a gun, then why are you even going there in the first place?
Let's just say that you feel that someone like James Eagan Holmes is not going to deter you from going to the movies, and that if someone like him does shows up, you'll show him who's boss. But if there's one thing to learn from Aurora, it's that the crazy gunman that you are trying to protect yourself against, already expects you to have a gun. That's why James Eagan Homes was wearing protective gear, fired off smoke bombs and what have you? So why didn't you bring a bulletproof vest and a gas-mask to the cinema too? Case in point: in the Aurora shooting, people in adjacent theater got hit too, so sittin' pretty with your concealed handgun when stray bullets are flying through the walls, seems like a dumb idea. Vest, helmet and gasmask should be the first thing you pack, only then should you think of your sidearm.
When I was a soldier (in peacetime), we had guard duties around the base. We carried live ammo and a fully automatic rifle, but it was never locked and loaded. It may seem stupid to walk the premises without being fully prepped for action, but the reality is that the number of people killed because of stupidity by people carrying guns far outnumbered those killed by intruders. People got killed for all sorts of reasons, but cheifly because of stupidity. Being forced to spend that one split second it takes to arm your weapon, is enough that your brain kicks in going "are you sure this is a good idea". In 99 out of a 100 times, you back down. Killing drunk kids climbing the fence for kicks is a terrible choice to make, just as it is killing people that are pissing you off in a theater.
So, by all means, when you've packed your bulletproof vest, helmet and gas mask, then pack your gun, but make sure you keep gun and ammo separate, so you have that split second to think about your actions. In Aurora you surely would have had time to grab your magazine and load your gun before you got shot.
But remember - James Eagan Holmes was expecting gun-carrying audience members, so you'd have to shoot through the smoke, aiming for a head-shot to take him out cold. Granted a few good body shots might have stopped him too. But James didn't care who HE is hitting, so he's just firing at random. But you - on the other hand - only have one target. A target that is moving, wearing protective gear and hard to see on account of the smoke. A real challenge for any wannabe hero.
Now the chances of James Eagan Holmes walking in while you are watching the 4 pm matinee are slim. Very, very slim. And the likelyhood of you becoming some sort of hero, when people are screaming and running all over the place are zero to none. I'm not denying that shootings do happen, and that the shootings happen (seemingly) quite often, but people win the PowerBall too, yet I am not constantly contemplating what to do if I should win, making precautions, updating my will in the event that I become a multimillionaire next week. Something else that is rare, is the chance that you, in a heated argument, kill the father of a 3-year (not accidentally, but on purpose and out of sheer stupidity), that your 6 year old son found your loaded gun and shoots himself, a friend or even you, to death.
We tend to remember the dramatic episodes, the big bangs, much more vividly than the smaller, almost everyday occurences. When a single kid is shot, it's one of those things we - as observers - almost immidiately shrug off and call it part of life, but when mass murder happens, we make movies about it, we demand legislation to be written to prevent this from ever happening again, and we carry loaded guns around in public as if it was a war-zone.
We had movies like Elephant and Bowling for Columbine made when these tragedies happened, naturally the media will instill fear in you, just to keep you glued to their broadcast - making you think "this could happen to me too". You don't see any movies being made about the hundreds of people that every. single. year lose their children for something so - demostrably irrational - as having a gun in the house.
There's no argument that can be made, that will convince someone with an irrational fear of something, to change their minds. We are beyond rationalization here. It's like fear of flying - it doesn't matter what statistics you show people, they will always remember those episodes when the fear crept in, and now there's no arguing with them.
Granted, there are many other situations where a gun might come in handy - being mugged is a typical scenario that gun-proponents bring up. But if a lot of people carry guns, the assailant will simply shoot you from behind before robbing you, armed or not, you will lose in the long run.
I'm pretty sure Nancy Lanza has made a lot of the pro-gun arguments we hear all the time.
P.S. Writing this longwinded essay, I looked up Aurora shooting, Newtwon shooting, James Eagan Holmes, Adam Lanza and so on. So now I'm waiting for NSA come a knocking.
P.P.S. I don't think it is "ironic", it's a tragic coincidence.