One BIG problem... (SPOILERS)

I thought it was an interesting premise and I can see how the father would be put in that situation – the guy was a scumbag who raped his wife, but he knew about the hit-and-run, so he couldn’t turn him over to the police, and he couldn’t bring himself to killing him either – so he kept him locked up for decades. OK, I will buy that. What I DON’T buy is that he would burden his daughter with solving the conundrum. Why would he leave it up to his daughter to have to decide between two impossible choices – kill someone, or allow the family to be destroyed. At that point, it would have made more sense to not say anything and let the guy starve to death.

Another problem, this one not so big, is that the woman asked her contact at the police to check the prisoner’s fingerprints but then she decided to act before getting the results. Why? I suppose I could accept that she was so distraught over the whole thing and so eager to solve the situation that she just had to act right away, even though there was no pressing reason to do so.