Some people like things as efficient as possible. So why not hang a couple of branches on the ceiling with some duct tape and put some lights on? No space wasted, time to setup only 15 minutes.
Did they realize there wasn't another floor before constructing the stairs?
Some people are just not meant do do an engineer's job.
Another architectural fail. Or maybe a secret passage disguised as a ceiling.
Some smartass will eventually take a photo of the next guy's reflexion.