What a terrible teacher he is!!!

When I was in junior hige school, in swimming class, firstly I and my friends swam by following my teacher's instruction. The swimming normally bored us. But The time that teacher go to his room was coming!! We got a chance to dive into the pool because teacher prohibit to dive into pool. I and my friends did slow diving at first time, and the more time we was diving, the more quickly and higer we dived. It's a exciting!! But the enjoy time is not continue... Finally, the teacher got out his room. However, we didn't notice that. Then we dived into pool again. At the moment, the teacher shouted " What do you do!! You are fucking fool!! ". Then he bring us to pool side and hit us. Although the action that we dived into pool is bad thing, I think he shouldn't hit us.