There is a large keyhole in the door, and numerous geometric carvings on the door itself, including the inverted Y on a triangle shape often used as a symbol by the Cult of Tharizdun.

The door would open away from the cave by the looks of it, and some of the carvings could be used as handles.

Other than a huge amount of foul-smelling blood, Eilyra finds nothing with the dead bloodhulks.