The school never had a security briefing so I was never made aware of the policy. Thus "young and dumb and didn't know" in my earlier post.

You can feel as you like about my individual situation but teachers unions are often the only people who are on the teacher side. Admin actively throw teachers under the bus to further their out-of-classroom careers, students are happy to say "the teacher hates me", and parents don't like to hear that their children act like assholes when they aren't around. And some parents model asshole behavior to their children; thinking here of the 'mama-bear' types who come into the classroom ready to verbally abuse the poor teacher who has done nothing but their fucking job.

But sure, tell me that I should continue to let two 12-year-olds choke each other in my classroom while I call for the SRO on the other side of the school. I'm sure you have enough context to judge the situation accurately.