Assuming, of course, the player had the Mavin in hand, which wouldn't have been the case if they were going through the Stout Mines....however...
it would have been interesting, for any violations of the Sacred Oath prior to picking up the Mavin, that as soon as the characters went to pick up the Mavin from it's altar, WHOOOSH!!! Black fire descending from the heavens, immediately annihilating all of them!
-Sazerac