[@CollectorOfMyst] Luckily, not indefinitely ^^! It's only possible to draw 12 Rooms maximum (the ones that have the Exploration Tokens on them). There are currently, 8 Tokens left for this mission. As for corridors (Corner pieces, short passageways, T Junctions and Cross paths) there are more of them then there are rooms, though again not an infinite amount. I'd have to count how many, though.

It is possible to fail a mission from getting unlucky with the room draws/Exploration Tokens and not finding enough clues, like you suggested, though. The larger the mine gets, the deeper you explore, the harder it is to keep the evil Darkness contained in the mine, but the more potential experiences - and thus rewards - you might find.

This is all based on this mission type, though. There are alot of missions with Fixed Map layouts that follow very different rules.

Anyway, I'll set the new room up for you guys now~!

EDIT: Lol chores