Personally as a teacher, I'd give the her the benefit of the doubt.
There may well have been time restraints, conditions imposed by the pool, previous student behaviour etc. to be aware of. Whilst certainly, some teachers are unnecessarily harsh, an outsider has no idea of why the teacher is giving the instructions that they are. Unless something is obviously abusive, I don't think it's fair to be judging the teacher when you don't know the details.