For what it’s worth, a taping the teacher would be a problem in my school.
Phones are supposed to be off, and in lockers. You’re not supposed to have the means to record anyone.
What this teacher has done is wrong. Don’t compound it by taping her-- that changes you from the victim to someone else who has no regard for the rules…
If administration wants to tape her, they can. Apparently there’s already a history here, and room full of kids to back up the story.