During one of our lectures, the center divider was left halfway open, revealing the operating room side of the replica hospital. Unfortunately, I was sitting in front across the operating room. Halfway through the lecture my eyes got tired, so I took my glasses off and zoned out. I caught myself staring at the operating room door, which had a small glass window. I watched as light reflected on and off of it. At that time, I was thinking that the light was coming from car headlights outside -but wait- we were on the fifth floor. Realization hit so I put my glasses back on and took a good look at the door. The reason why light was reflecting on and off of it was because it was swinging back and forth, at a consistent speed as if someone was playing with it.