"The truth is the death toll is almost certain to have been higher if it were not for the armed guard or guards or reacted and panicked the shooter into committing suicide."
That may be good enough for you, but I bet her parents would disagree that it was.
Like I said, if we can keep it down to just a few kids being killed, by having guns in the schools, to stop the mass killing, that is good enough. Unless, it is your kid that is killed of course. Let's see what the next one brings. Maybe every teacher will have a gun in the next school shooting. Problem is if the first shot is not at a teacher, or there is not one in the hall waiting for the deranged kid to enter, and start shooting, there still is going to be kids shot, and possibly killed.
What happens if the deranged kid walks up to the teacher hiding the gun, pulls it from his pocket and shoots the teacher before they can pull their gun. Then the kid just turns and starts firing into the classroom, because he knows there are kids there that he has had problems with. By the time another highly, tactically trained teacher responds, it will turn into a mass shooting, before he even decides he is out-gunned, and commits suicide. He may even like the challenge, like it is a video game, and actually want the extra competition to see if he can, "WIN". What happens if the guard, or the teacher that is responding, is also shot and killed by the deranged kid? What if he decides that suicide is not an option? In the meantime the bullets just keep flying around the school in an all out shoot-out. Who is "Winning"?
Looks like Israel would be a perfect place for you to live. I am not so sure the majority of people in this country would agree with you, that our schools should be like theirs.