Perhaps it generates the map as you explore? And in dungeons, once a certain amount of map has been explored it then generates the exit?
All the same "RANDOM".
05/11/2012 23:37Posted by TerminatorDhttp://i211.photobucket.com/albums/bb273/danhogg/maplayout.jpg
LOL. This happens to me too all the time. I have gone through plenty of maps like this one in Diablo II as well as Diablo III, and although I cannot remember for sure, possibly even in Diablo I :-)