The Entryway to the Ithrilis Temple                    -      N      - 
(-------------------------------------------------)     - <---(M)---> -
                                                        -      S      -

Beyond the iron gate is a small enrtyway that has been protected from the
lake.  Despite the fact the floors are dry here, your feet are still wet. 
There isn't a lot of light in this room at all, but you do manage to spot a
small staircase decending into a dark halway to the south.  Being that the
only other exit to this entrance is south, that must be the way you have to
go.