I get something similar i suppose like that alot......

Used to have a recurring dream when I was younger, and It was about some lizardmen keeping lots of people i know from school in a prison, which was pretty much like it, with vents leading between rooms etc....

Had one recently too which maybe fits the mixing a little more....

There was a pantomime about to start, and in the foyer at work (its a supermarket) we were selling tickets to see the show... and id go through to the projection room which was my office at work, and there was a projector pointing out of the wall (its an outside wall) with the theatre like area just through the wall, kinda looked like it went into the ground a bit, not to mention 2 traintracks run right through it

Seems to be common with alot of people then