Well, if the past is any guide, and it never is, but one common thread in all these shooting is A. Ignorant Shooters B. Inadequate
response.
When the first shots are fired IMMEDIATELY THROW THINGS- books, desks, chairs, salt shakers, laptops, shoes, whatever DIRECTLY at him/her.
It will discomboobulate him/her and throw him/her off stride. These goblins are not Special Forces Assassins or Army Rangers or even 20,000 rounds a year target shooters. They are monkeys with dangerous implements who will revert to stupidity under stress when challenged.
You can not assume the goblin will come through the door. He/she could be sitting right next to you or at the desk at the end
of the aisle.
Instead of worrying about where to sit, develop a keen interest in manner and style of dress of everyone you meet. Look for weapons printing through clothes or affectations out of context with the immediate environment. Make mental notes about deportment and demeanor. You may spot trouble weeks before anything ever happens.
In the Virginia Tech shooting the guy practically sent up flares he was wacko.
DO NOT CO-OPERATE. Make him/her work for his/her moment of fame.
In the Virginia Tech situation, the guy was reloading after everyone was lined up against the wall.
Why make the simple complicated? Remember THROW THINGS and DO NOT CO-OPERATE and your survival odds will skyrocket.
That is all.
Good points, although throwing things will make the bad guy focus on you. But that's ok, as noted it will divert him somewhat and maybe discombobulate the shooter a bit.
As in the Co. Springs church, yelling also works. Jeanne Assam kept yelling Surrender at the shooter as she shot and moved toward him. In a different situation, yelling will also draw attention toward you and disorient the shooter a little.
However, you must first decide - what is my mission, escape or confrontation? If you're trying to escape, drawing the shooter's attention is probably a tad counter-productive. On the other hand, if your intent is to stop the shooter, move towards him rapidly, keeping him disoriented if it is appropriate.
HOWEVER, DO NOT HAVE A SET PLAN!
The shooter is almost guaranteed to do something not in your plan. Rather, train your reactions. Assam took cover at first (training) then realized it was an active shooter scenario, and moved toward the danger with her weapon. (more training). When the shots get fired, you probably can't trust your mind to reason out everything, you have reaction (body trained) time.