I wasn't too concerned about the contrivances in the set-up. It was inventive and maybe not so credible, but still necessary to set up the central dilemma.
I was intrigued by the cruelty to the "old woman." It seemed to me that the whole village depended on her, in one way or another, and yet they abused her. I can understand withholding the water from the pair when they were not working, but why the voyeur scene?
Also I'm still thinking about the ending. Not sure the movie earned that. If he had pleaded for the woman's safety when she was taken away or in any way shown how committed he was to her (maybe that was clear and I missed it), then I'd be satisfied with his staying. I can see that the research was important to him, being a scientist and all, but that didn't seem important enough to hold him in that situation.
What am I missing? Is it all an allegory and only that?