[TRUE] janitor [M] in an all girls school

I’m new to this and decided to write a story that has happened to me before.
I used to work as a janitor in an all girls boarding school. I worked nights in the boarding halls every three nights.
The rooms were often in fours although some had their own.
One day I was starting my shift and got told to watch of for four girls who were in a relationship and had been split up because they had broken rules on a “no affection” rule the school had. I didn’t see them until a few weeks afterward they were walking down the corridor to the toilets. I decided to check on them after 20 minutes I was unsure if I was allowed being a man so checked with my supervisor who worked in the main building and was told I should do so but not. As I approached I noticed music from the toilets and knocked since I had no reply I decided to enter. What I saw was very different. I watched from a small opening in the second door. The room was dark and was hard to see someone if they were stood or at least I thought it was. They were all completely entangled with each other. I watched as they were fucking each other so rapidly one girl was lying on the floor as two were on top of her with one scissoring and another being eaten alive. The other was endlessly kissing the first and really making sure that they were having fun. I was stood for almost five minutes watching them fuck until I was messaged by my supervisor and left to speak to him. I told him that I was mistaken and that they had left and gone to there rooms. He made a quick joke about how my eye sight was terrible. I went back in and continued to watch for another ten minutes before it looked they were almost finished and quickly escaped.