Level 4 - 2,7,4 - a crack to squeeze through

I entered this at 2,7,4 - there was a 3x3 water room with quicksand in the middle, and a door.  the door leads to a long hallway, twisty.

2,7,4 is AM, as is all of the water area beyond the crack that i can find.

I have tried banging on all the walls, etc.  I can't find a non-AM square to WoR out, in effect I am trapped.  

Does anyone know how to get out of here?

Look for Strider, fists of fury, :King Weasel in the game if you know the secret handshake...