The pros and cons of having armed teachers in schools to protect pupils from terrorists and other crazies

In several U.S. states now some teachers are being armed with pistols to defend the children in their charge and to give their lives if necessary in this defense of their children they are responsible for.

However, what is important to remember is that this is sort of like wearing seat belts in cars in that
all results won't necessarily be good in the short and long run. In fact, to me it is exactly like wearing a seat belt in a car:

First of all, some teachers aren't going to do well if threatened by weapons from terrorists or other crazies. It is hard to sort out who these teachers are going to be. So, likely you would want to train teachers carrying guns to protect their students and to fully impress upon them if they have to use their weapons that likely they are going to die or be maimed or injured in doing their duty protecting these children.

Otherwise, unless the seriousness of all this is fully understood like police and soldiers have to be also taught this, bad things could happen regarding having armed teachers in public and private schools around the world and in the U.S.

So, expecting to "Kill or be Killed" is probably the first thing that should be taught teachers.

The second thing that would need to be taught is if you ever fire your weapon in a situation like this you "Always shoot to kill and not to maim" because otherwise things can easily get out of control and cause the deaths and maimings of many people in these kinds of situations.

So, without training people to use "Kill shots" only and not trying for an arm or leg wound it isn't useful for teachers to carry a loaded gun in school.

Also, if they weapon isn't loaded it isn't very useful in time for emergencies. So, likely it would be kept in a lock box rather than on the teacher's person in a concealed manner. You would not want teachers to "open Carry" because then students might playfully take the weapon when the teacher wasn't looking and accidentally or on purpose shoot someone with it including themselves or the teacher who was responsible for the weapon.

So, basically the training both physically and psychologically for training a teacher to have a loaded weapon nearby would be almost or completely like the training for police or Soldiers worldwide.

Except in the case of teachers the question becomes: "How do you keep this loaded weapon out of the hands of the children in all cases?"

So, basically said the solution might turn out to be worse than the problem being addressed in some cases.

The probability of needing a weapon should be run mathematically to see if it is worth the risk involved having loaded guns around children in the first place.