We have three parallel threads running in the aftermath of a tragedy. I thought I'd start another one, trying to filter out emotional and other components and get to discuss what/how/why should we do if faced with a similar situation. Moderators: if you feel this can be merged with any of those threads above, feel free. What I write here is a synthesis of my own thoughts as well as what I've picked from reading your ideas.
#1. Mindset. I think DocGKR mentioned that when going to mass public events one has to expect bad things. I agree with this. I've carried to public events in very non-permissive environments for awhile. When not able to carry firearms, carry nonlethal - tacti-pens on airplanes etc. Realization you better off carrying something is as important as what you carry.
#2. Mindset. Multiple examples suggest that aggressive, decisive, unexpected actions win fights, at the minimum change course of events. One can make his/her own pre-planned decision on course of action - engage actively, engage opportunistically, flee, hide - depending on own preferences and values, but it seems that whatever you do, bold aggressive action pays off. Feel free to disagree.
#3. I did want to put situational awareness here, but I am not sure how to plug this in. Not sure how to be situation-aware in a dark movie theater watching a movie. If movie is any good, then you'll be staring on the screen. Perhaps training self to redirect attention from the screen and survey the venue at times? Discuss.
#4. Choice of location. Most of that has been discussed in other thread. Still, quite a few variables. Most would prefer best vantage points. Some want to be closer to exits. In venues seemingly isle seats are better than center for easier mobility, although they have own disadvantage. I prefer to sit near/over the exit ramp with idea that my family can jump there from above if they can't make it to the exit on foot.
#5. Communications. Some of it comes from John Farnam who teaches that families/partners should develop a set of defined commands. For example, children are to be taught that certain commands are to be followed with immediate response and zero arguments.
#6. Choice of equipment. I am asking myself: if my goal, and the source of concern and planning, is to spend 150 safe minutes inside a decidedly low-light environment, then why would I continue the routine AIWB thing for those 150 minutes and not click on the X300 and carry it strong-side? I am not even mentioning not carrying a handheld flashlight here, that to should be a given.
#7. I don't think we could come up with a specific type of action given variability of every possible scenario. One question I've had for myself even before this accident: if I see a heavily armed man in clothing that precludes from recognizing presence of absence of IBA, should CNS then become a target? I don't know if there is a lesson to be learned here, but if there is one, I'm sure that late Mr. Wilson would want us to learn it.
I am an amateur in this and I am not trying to play tacti-armchair commando. Simply an attempt to come out with something constructive.