In Dungeon's Deep

Squeeze into the dungeon and follow it to a large spiked block, belay.

The bridge of Kazad-dum: Follow 2 bolts out to the Balrog block and battle past it to the escape hole.

Variations: Hobbit Hole Escape or Shelob's Lair

If you don't want to fight the Balrog there are 2 easier escapes from the dungeon making the whole thing an adventurous dark scramble of low 5th class.

2 Bolts