Theme: Unstable

Concept: You are a miner in a cave, the roof of the cave is unstable. Over the course of 5 minutes, as the minutes go by, the chances of it collapsing grow greater and greater. You have to mine as much gold as you can. You can either play it safe by taking a little gold and exiting quickly, or you can try to maximise profit by staying in the mine longer, but you might die if the cave collapses on you!