Try looking around at the wooden suuports on the wall & maybe even clicking on them.
HUGE WARNING
If you *DO* go clicking on the supports i would suggest not standing directly under them
Its part of the game storyline as you cant access that area of the map if you dont make a way for your party through that tunnel. (There is a door but you need to be able to access that part of the map
before you can find the key for the door.
Hope that helps ya.