When you're dealing with hormonal teenagers changing the gender of the instructor in the room sometimes totally resets the dynamic. Which can be useful when the dynamic is temporarily off the rails. Worked often enough to be useful when I did study hall/tutoring for alternative high school students. "Hard day? <silence> Have a seat. I'll check to see if you want to work on math later." Worked surprisingly often.
Is that what we'd call detention in the UK? I've always believed that a cool-off period is one of the best ways of defusing an angry situation.