[LanceH]

The ground might be softer in one direction. There may have been something worth mining out in a specific direction. Of course this only occurs orthogonally in the real world :) The main point is that with mining a tunnel is the natural structure and rooms would be unusual.

An empty hallway is great for storage and requires much less support than building out a room. It could also be explained by venting or similar that might not show up on a map.

[mcguire]

"Gettin' ready to carve out the Master Dining Hall and what do we find? It's smack dab against a vein of mithril ore. You know what happens when you start digging mithril, right? We ain't doing that for no union scale!"

I used to work at the old IBM buildings in Austin; there were a few halls that went around a few corners only to dead-end. With a bunch of spare desks and chairs piled against the end wall.