Crack.
The rune which you could have sworn was stuck fast inside the walls of the cavern dislodged as easily as a bird's nest. It tips over and out, your jaws struggling for purchase to no avail as it clatters noisily to the floor.
Your heart pounds in your chest -
CRA-ACK
Whatever mysterious force that held the collapsing stone and ice at bay was failing, and your time was up. You hastily scoop up the tablet as you beat a hasty retreat, blunted claws scrabbling against the smooth ground; the distance toward the exit seemed to span an eternity when before it had felt so short, so easy. Your lungs burn as you realize you've been holding your breath, throat tight, teeth clenched, grinding against the pulsing blue stone -
And you're out.
The cavern collapses behind you with a terrible sound, and you lay sprawled across the snow as the rune at your side pulses once - twice - then fades to a steady, gentle glow that does not extinguish.
You are successful. While no voice is there to praise your efforts, you feel hope stir anew within your chest.