You are never going to have a large percentage of the population carrying guns. They get heavy after a while and most people start making excuses to not carry. So, the “room full of shooters” scenario is unlikely unless you are in a gun store or cop bar.
Likewise, no one is going to draw their gun and hunt down the shooter. That’s great in movies, but in real life, you tend to focus on you and the people around you. Being mistaken for the shooter as you hunt the real shooter, Bruce Willis style, is unlikely.
When (If?) the cops come in, you can drop your gun and raise your hands because that’s what they’ll be ordering very loudly as they enter.
Staying low, hiding under desks, crawling into a closet to hide are excellent ideas. No one wants to be in a gunfight. But if you can hide, draw your handgun, and wait; you are better off than just hiding. Sometimes, these office shooters look under desks and then your hiding place just became a trap.
>>Being mistaken for the shooter as you hunt the real shooter, Bruce Willis style, is unlikely.<<
I just noticed your name, DieHard the Hunter, after I posted this. Your attitude towards guns for self-defense is kind of obvious and your choice of screen names proves it. :)