A Dark Tunnel                                          -      N      - 
(-------------------------------------------------)     # <---(M)---> -
                                                        -      S      -

The air here is wet, and the heat is uncomfortable.  Against the hard
packed wall, covered in grease, you can see the shadows of men and beasts,
walking along in chains.  You hear a primal scream let out from down the
tunnel, the scream continues, and you are forced to cover your ears to stop
the incessant pain.  You notice guards all around, and decide that you must
continue your journey.  A thick iron door is set in the west wall, with a
small hole on the front.