Nope. Consider these facts: If you are the only adult in a classroom full of kids and a shooter breaks in...
You can't run away.
You can't hide.
Begging, pleading, or crying and stalling for time won't work.
Furthermore, you nave no access to firearms, you may well be physically weaker than the attacker, You are caught by surprise, and you will have at best minimal physical and mental training.
So what do you recommend?
In theater Foyer entrance, I asked the guy yo go outside as we were locking up after the concert. (* The old theater had been changed to a concert location *).
He pulled a small revolver from his hoodie and I raised my hands and said "you win".
He asked "What did you say?"
I stepped closer and said "You Win" - Just a little louder.
He said "What?!?"
I said in a normal voice now within range of him , "You Win, what do you want?"
Out of the corner of my eyes I saw police outside and out of his view. So I choose not to act.
I stepped back and asked again "What do you want?"
He said, "You are crazy, pocketed the pistol and walked out into an ambush to be tackled.
This assumes that the person was not there to assassinate me directly.
It assumes that they are not there just to create a body count.
I created a diversion and engaged them with words that they were in charge.
(* Yes it did happen *)
Now I know what the next question will be . What do you do if they are there for a body count or to kill me directly.
The Assassination is the most difficult as they are there for a reason and you are the target, and most likely the first person shot is either the person that notices the firearm or their target.
In this case - Don't be a *insert derogatory descriptor here*.
For the body count, it all depends. It really does.
If you can attack from the side great.
Now to the classroom.
What is the fire escape route when the fire is right outside the door?
is it out a window? Or is it barricade and hope they get to you before the smoke does.
Assume there is multiple exits not into the same hallway.
Take the alternate exit. Call for the children to line up for the fire drill.
Have them exit the building - via door or window and check the room, and then leave.
This builds upon an already established and usually practiced a couple of times a year drill.
If no way to exit, then barricade the door. Figure a way to wedge it shut and or prohibit the door from opening with a chair or something else.
It is difficult. I do not see a 100% way to resolve this issue.
To get further into more details could lead to a post being called political and I am not trying to bait anyone into doing so.
So let us keep it to these details for now.
Not the best, just my best at the moment.