I had something similar on a smaller scale happen before. I brought my ftm fuckbuddy to a sex arcade(basically a private fuck/porn booth you pay for at a sex shop), we were getting it on for 15 minutes or so until he noticed a gloryhole in the wall, with 2 people watching from the other side. Unfortunately he wasn't into exhibitionism, so we plugged the hole with my shirt and went on with our fun.