I just started the DLC, got down to level 4. On the way there I dropped some loot to get rid of encumbrance on level 2 and 3 assuming I can come back later and pick it up. But when I tried going up from level 4 it brought me straight to the surface and when I entered the dungeon it brought me straight to level 4. I found no way to revisit previous levels. This is really frustrating!