Holy Ghost!

So I went into work for a few minutes tonight to pick up some headphones I left in my desk. I needed them because apparently the music I listen to and my singing along is offensive to nameless roommates. Now they just have to listen to me sing with no music. They'll be sorry. Anywho, I swipe my card go in and turn off the alarm. I'm putting the key in the door and I hear "Hey!" over my right shoulder. Well of course I screamed for about a full minute and then I turned around to see who else was in the office on a Sunday night and its no one! There is not a soul there. I walked around a bit and was yelling out "Is anyone here?" to which there was no reply. In retrospect I'm glad there was no answer since there were no living people there. I probably would have wet myself if I heard a reply.