[Wonder Warthog]

"The thing is, most teachers won’t volunteer. And of those few who do, are they capable of acting as the police did in that video?"

And you know this how? Interviewed any teachers? And they would not need to "be capable of acting as the police did in the video", as the circumstances would likely be much different.

[CatHerd]

Yes, I know quite a few teachers. All were horrified at the idea of having to double as armed guards. How many have you interviewed?

You might imagine scenarios where the teachers would not have to operate as the Nashville police did. But that does not mean the teachers would not have to. And most teachers, especially those who teach early grades, are simply not cut out to be Annie Oakley.