some of the tombs the entrance locks on you, if its locked up and your follower is in there, they can't get out to walk home. There was one i spent the better part of a hour to get up on the ledge for the back exit only to find that the exit door itself closed as well. later on I was able to enter again via another mission, but what i was after was gone by then.
It's where you pull the chain and the hole opens. You fall down into water. Then you make your way through a flooded corridor to a room with 2 sets of "stairs" and a bridge with scythes going across it. I'm not seeing a way out of this....Now I think I remember why I stopped playing for 3 months...
oops wrong one, sorry, yeah that one i dont believe there is a way to get back to it other then the front door. I had a follower not follow me down, i just reloaded though.. I tend to save just before jumping into a pit

habit from other games lol...