First a description of the building.
It’s shaped like an L and it has doors on each end. The shorter part is the office and lobby where I work and the longer part has a bunch of smaller offices. The inner corner of the L shape also has doors on each section that lead out to a parking lot. One of those inner corner doors is connected to the lobby and the other leads to a dark narrow hallway (known as “the Batcave”) which connects to the main hallway of the long row of small offices.
The guard went out to the parking to clean his car because there’s not much to do today anyway. He saw some lights from the long row of small offices and asked if there’s anyone there. I truthfully told him people go home and leave the office lights on and only our side of the building operates at night. While he was cleaning his car, I went around the long way, through the hall and started turning lights off and on in the office where the company founder’s ghost is said to reside. I heard the guard drop something and scramble to his post, tripping over himself, before coming out of the Batcave door to the parking. He heard the door and froze, wide eyed, then nearly choked in disbelief when he saw it was just me. In his own words, I scared him shitless.