Admit I'm a bit skeptical about arming teachers. Not real sure than some concealed .380 pocket pistol with 6-7 rds. is much a deterrent to someone carrying AR15 and 30 rd. mags in a hallway shootout. Same goes for a larger, harder to conceal full size 1911 or any full size 9, .40. .45 with limited ammo whether 8rds. or 18 rds.. Theory being said teacher would confront the perp in a shootout is a fallacy.
There is no, legitimate plan that involves teachers in hallway shootouts. It might play well in movies; but it does not match reality. The discussion involves teachers being able to secure their room and prevent armed entry.
The current doctrine is that the teacher and students should throw any available objects at a shooter forcing their way into the room. That would be things like nerf balls, lego pieces, and a stuffed toy rat. I cant believe that, at ranges measured in feet, not yards, that a stuffed rat wold be more effective than, even, a .380. Yes, I have heard people remark about .380 caliber pistols, things like "if you shoot someone with that, and they find out, they are gonna get real mad." Frankly, I write that off as ignorance and too many action movies.
I suspect most teachers are vehemently opposed to the very idea non-LEOs can own guns in the first place. So as with allowing concealed carriers to carry, the idea of "arming teachers" would involve those interested in doing so rather than those who do not.
The issue with police shooting anyone they see armed is a problem with policing, resulting from the drug war--the idea they are the blue line and we are the enemy.
As I mentioned in another post, this reflects a conversation with another teacher on the subject:
This issue seems to be gaining traction. I just had a couple of non-shooting, not anti, just non, teachers ask me my position in this issue. The inquiry was unprompted and my position was taken seriously.
I think my nuanced position did surprise them as I am generally a bit to the left of most of the teachers here.
As far as the other part of your post. There is no real plan that involves the teachers running around the halls with guns. The discussion involves teachers being able to secure their rooms. We already have Faculty vests that identify us as Faculty and are quite visible. The opponents of allowing teachers to actively secure their classrooms seem to have watched too many action films.