Yes, I've yelled at my DD, but nothing quite like what I heard coming from that room. I'm sure if I yelled that loud, that I would be feeling like my head was about to explode. I have nothing wrong with a teacher having a stern word, but it was far from being that.
Another mum who was there was laughing at the start, she thought the teacher was role playing or something. I think we were all sitting there with the same stunned look on our faces lol.