Prisoner
When they leave at night, she's all alone. This would be no punishment to a cave-dweller except for the worry that it's all a dream within a dream. She could wake up back on the furs, back with the shadows on the wall and the pool of water.
There's no way to tell.
Water comes from a tap, here, and she didn't forget it. It's just hard to believe that she has a door, and a lock, and no collar. There could a dimension ripple at any time.
At night, she sleeps in his closet, where his shredded leather coat still smells of woodsmoke.