Sandbox Campaign Part 6: "This is no mine. It's a tomb"

This is part 6 of my ongoing account of the sandbox campaign I am currently running.  Updates are frequent, if irregular, and at the end of each post I talk about one or more subjects pertaining to the adventure but more broadly applicable to all campaigns.  You can find the previous parts here.

After resting up from their encounter with the flail snail, the party crossed the stone bridge over the chasm and found a chamber abutting a stone wall, featuring a door flanked by two dwarven statues.  After dispatching a trio of cave scorpions, they were able to make out a dwarfish inscription above the door that read:

Into this place let no enemy creep 
douse all lamps and into darkness leap