I am not a cop and am only a sheepdog for my herd - not the world in general. But as that sheepdog it is my job to get my herd away from danger, not to abandon my herd to confront the danger. That step happens when evasion and escape have utterly failed (which of course means they must have been attempted before being declared a failure).
When things go south the basic steps are 1) get the herd to cover, 2) figure out what is going on and where it is going on, 3) figure out how to put distance and time between the herd and trouble without exposing the herd to more danger, and 4) execute. Nowhere in that plan do you see drawing or shooting. Those steps are part of Plan B, for when Plan A has failed.
As forI offer the suggestion that you and your daughter assess the probability of those situations rather than the possibility. Even with the most probably one a healthy dose of "Don't go stupid places with stupid people to do stupid things" goes a long way towards reducing the probability - listening to the gossip and watching how the crowd flows (especially away from certain kids), making your home uninviting to invaders both physically and by your behavior, situationa awareness along with the "no headphones/earbuds, no talking on the cellphone while walking/driving" rule.Another question for those of you that have kids... How do you talk to them about what to do if something like this happens without scaring the sh!t out of them? I have a 13 year old daughter and we have discussed school shootings, home invasions, attempted kidnappings, etc... and I'm afraid she's going to go agoraphobic on me if I through something else at her
Depending on how mature she is you could consider making your daughter an active part of the defense plan instead of just another lamb to be herded. Pointing out situations and persons and asking her to tell you if they are (to use the infamous situational awareness color code) green, yellow or red. Asking her what she would do if "X" happened, or even how to decide it was time to be elsewhere before "X" happened. If she's not up for that yet, your daughter might be calmed down/less paranoid if she just had a basic set of steps to follow when Daddy declared that life had just gone all pear-shaped - which side of you to be on when she gets behind you, how flat on the ground she is to be when you yell for her to "Get down", and that she should grab your belt as opposed to your hand when you are running away.*
For kids who are not staring down the barrel of a gun, school shooting responses of "getting the heck out of dodge" usually have better outcomes than hiding under the desk waiting for the shooter to find you. It does, of course, require that the person doing the E&E figure out where the danger is and then a route away from it. She has an "X/number of rooms in her school" chance of being caught in the actual shooting incident at school - awareness of the probabilities as opposed to the possibilities can go a long way towards keeping calm. The other part is how you get her to understand that she must disobey the instruction to hide under her desk and instead leave school without "official" permission - as well as how to do that (what exits are available? can she really get out a window? why it is OK to break the window if it won't open but otherwise would be an escape route. Etc.)
Mass shootings like the Aurora theater incident are, at her age, more likely than the Trolley Square mall shooting (based on my completely uninformed wild guess that you do not yet let her wander the malls without an adult). There the best thing seems to be to get low and stay put - unless the shooter she is dealing with starts walking the aisles and shooting down the rows of seats. Then getting under a seat and becoming "invisible" might be the better choice than trying to get to an exit that is probably already blocked by a stampeding mob.
Finally - while the discussions with your kid(s) is important, it is not something that needs to be made into a planning session for the re-invasion of Fortress Europe. You can also get your daughter to become engaged in developing a sense of situational awareness and working the OODA loop by throwing sudden, unexpected rewards her way when she demonstrates her ability. (After umpteen discussions with my kid, and countless times asking her "What would you do" as I pointed out something around us, she one day out of the blue turned the tables on me and asked me that question! She got, IIRC, a set of earings she had been letting me know she reallyreallyreally wanted. When she did it a second time she got, IIRC, some extra time on the computer. The third time she got a pat on the head and told she was a clever child. (And yes, she got the message that doing the trick was not always going to result in a prize. But she continued to do it every once in a while to both show off her skill and to see if that time she would get a prize.)
Hope these ideas help.