I don't know about the building, but I was involved in some research on an abductee related topic.
In short, there's a known condition that creates the same elements that some describe as a visitation.
It's occurred through history, with similar stories, but with variations to fit the era. Early examples were visited by witche's, not aliens.
When we sleep, body movements are restricted to prevent us thrashing about. Too little control and we sleep walk, or fall out of our safe perch.
There are some where the mind wakes up, but the body is still in a sleep state, and rigid. The more you try to move, the more paralysed you become. In the half light, and half asleep, some 'see' or sense aliens at work, when it is just natural.
I don't know if that's any use. I just find it interesting.