How could any woman ask "what is the doctor going to do to reduce the flow?" I might understand if a man said that, I'd still think he was a bit period ignorant, but at least he'd have the excuse of never ever having had a period so not fully understanding them. This is gobsmacking.
Re toilet breaks. Yes, there can be problems with some kids, there always has been I guess there always will be, but a good teacher and a well managed school knows when to accept that it is essential for someone to go to the toilet immediately. Some of the rules at the academy schools I know of are insanely draconian. I went to a grammar school about a million years ago, where good behaviour was expected at all times and we were given more freedom than some children today.
I feel awful for this poor, poor girl. It is disgusting that she was put through this and it's going to stay with her. I was sitting in an exam when I was about fourteen, not long into starting my periods, when I started to bleed really, really heavily. I was wearing a pad and I could feel the bloody dripping out from my knickers. I was nearly in tears, but it was an exam and I didn't feel I could ask to be let out. I just wanted it to end. When it did, the exam not my period, I sat there until everyone had gone out, got up, had to wipe the chair down because there was blood on it, go to the toilet deal with all the blood and spent all day wearing a jumper around my waist. I still remember the shame I felt on that day and no teacher had denied me access to the toilet, so god knows how she must feel/will feel.