That's a pretty extreme example to base a broad policy on. If someone (strong enough to incapacitate me) takes a serious swing at me, I would pull my firearm for a variety of reasons. Why is a 5' 2" female teacher duty bound to take a beating from a 6' 200Lb 17 year old? Just because they are at school?Yes, if they have a gun. You think there won't be a teacher at some point who decides to pull a gun because a kid takes a swing?
De-escalation training is still critically important. Yes, the response to a shooter/mass shooter is stop them ASAP. However, with access to a firearm...sometimes everything is a nail when you have a hammer to some people.
I completely disagree. Generally, the best way address a nail is to use a hammer. I don't think any civilian (or teacher) should be encouraged to gamble with dozens of lives. Nor should they be made to feel guilty afterward for not giving "rifle pointing Billy" a chance to redeem himself at the last moment. They should have a school named in their honor for ensuring the survival of every other child. The option for de-escalation expired the moment he entered the school -and- presented a lethal threat to other people there.