More important... the kid needed dunking. :~D
I bet this is a great teacher. He's been awarded as such in the past. We had a teacher in high school who would have done this, and had the respect of all his students because of it. I remember him making one kid sit in the trash can for a whole class, I forget why, but no abuse was alledged. Same teacher caught a kid chewing tobacco in class... at least he suspected the kid was chewing and had spit it into a Coke can. The kid denied it... teacher said... then you better drink the whole thing before class is out. If you don't, you'll be put in detention. The kid tried to drink it and threw up. :~D
He is a great teacher and that is why he will probably get fired or else if he is smart he will quit.
I would have gone to detention rather than drink that sloop. 8-)