Why do you have a gaggle of schoolchildren in the shower with you?
Or did you misread the question?
Oh, you want to know what I would do if I was hiding in a closet from an active shooter? Obviously I would pull out my M-16, kick down the door, then use suppressing fire to throw a grenade at the gunman. After that, I would just wait to be awarded my medal of valor.
I see you have no real solution to the situation.
Just a Rambo fantasy you use as reality.
Why is it my job to come up with a solution to an imaginary scenario I will likely never find myself in?
It is a statistically significant risk for much of the country/world, therefore it is part of being an adult, imo.
Not where I live, and I’m pretty sure the vast, vast, vast majority of people on this planet will never be in that situation either.
I’m sure you’ve spent your life planning for every unlikely scenario, but I have better things to do.