I like this premise: the dragon has become the mountain itself and its innards have become the caverns being explored. 👍 So if the pin is pulled and the PCs are still inside after 30 minutes... ?
...then they're probably toast, before too long! Unless they can cut their way out, or get Vylziangk to puke, sneeze, or... otherwise eject them. Maybe they'll come up with something clever! Thanks for your comments, glad you liked it =).
