Exacty the ending I was expecting for (spoiler, Dah!)

I simply knew it! Once the plot started to close endings, when Doug pushed Jen, I knew that if that movie is going the same direction I wanted it to go, the end will be death of Amy and the final scene will be Doug looking for the next victim with the camera in the bag, like in the beginning.
And I was very, very pleased that this film ended exactly like that.
That was the only solution, the only proper end.
Approving viewers' expectations is a sign of a great filmmaker, since he created these expectations in the first place.

Great movie. Nolan should learn a thing or two from it. How to create a character and identification with him, for example. Because this is what is completely missing in The Dark Knight.