This comment from poster "Dave" is spot-on IMO, if you are not an LEO, your job is to get out safely and call the police, that Dirty Harry mindset some folks have, does nothing but get more people killed:
1) Carry your gun. Always, every time.
2) Carry spare ammo. As much of it as you can. Test every mag you carry. Practice with speed loaders.
3) Carry a spare gun, if you can.
4) Your spouse/partner/significant other should (hopefully) be trained and at least minimally skilled with your carry gun and backup.5) As a non-LEO you are not a cop or security guard – you carry a gun to protect your life and the lives of your family. Your life and theirs are the first and only priority. Unless facing a direct and immediate threat to life or safety, do not attempt to prove you’re a better shot than the bad guy.
6) There may be more than one bad guy, and he/she may be posing as “just another customer.” Don’t tip your hand.
7) Never enter a walled or confined structure without establishing an exit plan, which may require being choosy about where you sit. In this case the LEO should have noticed the locked fire exit. If you cannot establish a good exit plan, leave. There are lots of restaurants.
8) Have a flashlight. If the lights go out you’ll need it to escape. Use it sparingly – a single light in a dark room attracts attention. And sometimes bullets.
(Tenring: WHOA WAIT A MINUTE, BUT ALL THE AR-15.COM "PROS" TOLD ME I WUZ GONNA DIE IF I DIDN'T HAVE A 500 DOLLAH FLASHLIGHT ON EVERY GUN I OWN, TWO ON MY AR TO AVOID SOME KINDA FLASHLIGHT PARALLAX TIME-WARP PHENOMENON, THEY SOUNDED LIKE PRETTY LEGIT OPERATORS....
9) If the poop hits the fan, imitate the wallpaper (see #5) and look for a way to execute your escape plan.
10) Stay alert. In lines, blade away from the counter to monitor entrances/exits, shift position to monitor 360 degrees, use reflections (glass, etc.) to see around you, around corners, etc.
11) If something doesn’t look right, leave. Leave now. There are lots of restaurants and other stores to shop in.
12) Spouses, and children, once they become old enough to understand, should be trained to follow parent’s instructions without hesitation. When Mom or Dad says “we’re leaving right now” (use of an “emergency” code word is a useful addition) Johnny or Susie should get up and go with the parent without discussion. This needs to be a family training issue, and the younger the child the harder it will be.
13) Spouses should have non-verbal signals for emergency situations. This means they have to have implicit trust in each other; if the instruction is to “leave right now” and your partner says “But Johnny hasn’t finished his hamburger” that’s something you need to work on. That trust goes both ways – either one of you may have seen something warranting an immediate exit. If it turns out to be nothing you can always go back in.
14) Spouses/significant others/friends/children should be trained to not say things like “Dad, you’ve got a gun, why don’t you stop/shoot him?” It may be quite prudent to not let others (non-spouse, friends) know you’re carrying.