The video I watched was very calm as it basically said 'if the shooter enters the room you are in, someone is probably going to be shot, but you all have to fight.  Throw stuff, rush the shooter, overwhelm them, get the gun away from them (but for the love of god leave it on the ground and don't be holding that thing when the cops show up!) get them on the ground, tie them up, incapacitate them, do *anything and everything you have to* in order to stop the shooter.'