Didn't anyone realize Carlos was a psycho killer too? That he was responsible for his parents "disappearance"? And because of that he had been institutionalized ("away") for many years when he was still just 16? That he was planning to kill Sam after the honeymoon? Probably using a climbing accident as a cover up? That the lady Carlos had dinner with, and who he also called "lonely" and "perhaps crazy" was actually Sam's brother, Steven? That the reason Sam fell in love with Carlos and thought he was "different" and wanted to "make things right this time" is because she unconsciously knew he was a killer just as her (even tough her split personality didn't allow her to remember being a killer at the time)? And that it was ironic because the one thing they had in common (which she unconsciously felt could make "things right") was exactly what was wrong with both of them? And that when Sam calls her brother on aswer machine you notice she is kind of whispering in the end? And that maybe that's her killer personality trying to come up? And that one of the picture-frames in Sam/Steven's house has a photograph of them in a background that clearly seems to be a wedding reception?
Still leaves a lot of questions to be answered and some plot holes, and still reinforces my opinion that so much could have been done and the ending should have been totally different, but that's the most i could get from the episode.