There's an elevator right next to my room. 

A lot of people use it. 

But sometimes, no one uses it. And it's still going? Like do elevators just go even if there's no one in there? Is this some kind of elevator secret I never knew before? Here's the thing:

Sometimes the elevator will chime and the doors slide open. No one gets off. No one gets on. The doors close. You can hear the mechanisms moving when you walk by. It happens periodically.