i have an idea, well, half an idea, its your idea with few modifications,
Maze:
Players: 3
Monster, Damsel, Hero
The Damsel goes in and hides. The Monster and The Hero enter and start to look for The Damsel, wichever gets to The Damsel first gets the reward.
If The Hero and The Monster get to The Damsel at the same time or meet each other in The Maze they will fight each other to The Death.
Post Script. please dont flame me for half stealing your idea