As Dustin pokes around, looking all over the chamber, he finds an area of the stone where there seem to be some depressions in particular form. They seem to reflect the light a bit. To those "in the know", you recognize the Undercommon script.
Under the inscription you can just make out a series of cuts in the wall, forming what appears to be seven buttons about a foot long and 7 inches tall in the rock face. If not for the light and close inspection, it's likely you'd miss them.
[ +- ] In Undercommon
For ascent, those most surrounded must retreat first. The unguarded will be the last to abandon their home.