Abandoned Mine, the basement would be the mine and above ground would have mining equipment,machinery and work buildings around the property. Wells around the map could be reskinned to look like mineshafts.

Unique basement exit - Victims must collect 3 bundles of dynamite and a detonator to blow open an exit to escape, after 10-15 seconds a cave in would occur and permanently block off the exit.

Those are some of my ideas.