A Dead End                                             -      N      - 
(-------------------------------------------------)     - <---(M)---> -
                                                        -      -      -

The main hall ends in a dead end.  The walls are bare, and a single lamp
in the center of the back wall provides just enough light to see by.  The
oily smoke isn't as heavy here, and the walls are a bit cleaner.  This is
probably due to lack of use, as no one would really have a reason to come
back here, except to light and refuel the lone lamp.