SPOILER: why couldn't they let the other family...
What bothers me after the film ended was that they could of let the other family go. Will's family just wanted to leave with some of the food rations that was theirs anyway. What was Paul plan if Andrew was sick, did he intend to keep them in the room or murder them in the end?...but to be fair Sarah was worried that Will might come back to attack them for resources later, still I think murdering the whole family was a bit much just for that reason.
Such a shame..I enjoyed the film but the ending was slightly disappointing. I'm giving it a 8/10 at IMDB because of the originality and twist that there were no supernatural monsters at the end only human monster.