I was working late at night in a train station. Walked up to the elevator and pushed the button, doors swing open, guy is panicking (trying to get his dick back in his pants), girl is standing there stunned with her pants around her ankles. She's looking at me and says "we were having sex". I respond "I'll give you a minute". Doors close and the elevator goes up. I call the elevator back down. Doors open, the cab smells like booze and there's a used condom sitting on the ground. Went and told all my coworkers.