Stormonu
NeoGrognard
Another thought, you could add a mechanic for characters to push their luck by willfully removing a die from the pool in return for some beneficial effect - a hint, advantage on a roll, rerolling damage, acquisition of a tangentially beneficial item, etc.
Furthermore, you can also use gradiants of the pool. For example, if the entire dungeon will collapse when the Countdown pool is exhausted, it could be that after a certain number of dice are lost, non-essential sections of the dungeon may collapse. For example, a bonus treasure room might become inaccessible after 4 dice are lost, the "short" route may become unavailable after 6 dice are lost and when 8 dice are lost sections of the main route fall away, requiring the characters to parkour, fly or otherwise get creative to make it out. When all 10 dice are gone, the whole thing falls away...
Furthermore, you can also use gradiants of the pool. For example, if the entire dungeon will collapse when the Countdown pool is exhausted, it could be that after a certain number of dice are lost, non-essential sections of the dungeon may collapse. For example, a bonus treasure room might become inaccessible after 4 dice are lost, the "short" route may become unavailable after 6 dice are lost and when 8 dice are lost sections of the main route fall away, requiring the characters to parkour, fly or otherwise get creative to make it out. When all 10 dice are gone, the whole thing falls away...