In high school a few of us skipped one afternoon and saw "Dawn of the Dead.' not normally my kind of movie, but what the heck. If you haven't seen it, or forgot, the zombies take over a mall. The zombies end up in the elevator. Some guy calls the elevator the door opens and out they poor.
At that same time I was working remodeling Dr. offices with a guy. To minimize disruption we worked 10pm to 4 am (Shh don't tell child labor) At that time there were five people in the building, two janitors, a security guard and us. The building was mostly dark. Our job was on the 12th floor, but our storage room was on the 5th. I can honestly say for a couple weeks I would hit the call button and back off to the far side of the hall.