Quote Originally Posted by Argus
In a collapsing dungeon, the rule about removing a room with any players still in it seems odd.

If you look at the example on page 29, it seems that the removal of room 10B is forbidden due to the empty non-stair rooms on the floor: The Chasm of Unnecessary Cliffs, Dungeon Corridor, and A Dark Room.

For that matter, if a floor has more than one set of stairs leading down to it, it seems that it would be difficult to remove a room once that floor is reduced to the rooms below and between the stairs.
Yes, there appears to be a problem with part of the example. At the end of the example on page 29, Belkar exits the dungeon and removes room 10B. The only valid room for Belkar to have removed is actually the Dark Room.

The rules say that you can only remove rooms from the left or the right, so removing the Chasm of Unnecessary Cliffs or the Dungeon Corridor would not be an option. Removing a room from the middle might cut off a character's 'escape route', and it therefore illegal.

Note too that there may sometimes be more than a single room on a level with stairs. This is fine - continue removing rooms from either the right or the left, but leave one set of stairs on the level to escape from.