Replying to Riddle me that

So, I'm a janitor at a school. I was in the middle of cleaning one of the bathrooms, so I blocked off the entrance. As I finished cleaning one of the stalls, I realized I had to shit, so I did my business, flushed the toilet and moved on to the urinals. At that point, I realized that someone had ignored the 'closed for cleaning' sign and made their way into the bathroom. Being on a strict schedule, I had to clean the urinals as quick as I could, regardless if someone else was using the adjacent one. As I approached the urinal, I noticed the man was wanking off into the urinal. Startled at what I had just seen, I stopped dead in my tracks and stared directly at the wall until he finished onto the leg of my pants.

So my question, NS, is what in the actual fuck?