Players take turns resolving the room in turn order.
The active player decides which room resolves first.
Thanks for your quick reply.
Let me show my understanding. Please tell me if I am wrong. (Assume the turn sequence is A>B>C)If Player A is the active player, he placed a map tile to complete a room which only have Player B and C in that room. The resolve action should be taken in Player's B turn but not in the active Player A's turn since Player A does not have any delvers in that room, and Player B would have tiebreak advantage in that fight with Player C.