Key tiles are drawn and placed like any other tile. To escape, each Prisoner must recover a Key from one of the Key tiles. To claim a Key, simply move onto the Key tile and place a metal Key token, from the reserve, next to your Prisoner Status card as a free action.
A player can only carry a single Key at a time, as your other hand holds the candle. Therefore, a Prisoner who reveals a Key tile when they already hold a Key is faced with a dilemma. If you walk away and no longer illuminate the space, the Key will be lost. Additionally, Key tiles are Crumbling, so if you walk through the space, the Key will be lost when the tile becomes a Pit next turn. If you block the only Passage to the Key, no one else can get to it.
But Keys MAY be passed. A Prisoner may pass a held Key to another Prisoner if, on one of the Prisoner’s turns, they are adjacent to each other and connected by a passage.
Passing a Key is a free action.