If you don't mind leaving behind some gear, it's not too hard:
- Go out of cell, shift sneak past first sleeping goblin by the south door.
- Keep going southeast,ignore the sleeping goblin guarding the key, keep going southeast until you go to the stairs
- Once you go to the second floor, goblins will automatically alarm, so no point shift sneaking, just run the linear tunnel as fast as you can
- Now aim for the west portion of the map, avoiding goblin patrols, once you encounter a big group you will be automatically alarmed and spotted, but all you need to do at this point is run straight south to the exit.