This ending has two variants, depending on whether Lauren is alive or not:

If Lauren is alive, she will rant atop Scott's and Rae's graves, criticizing them emotionally for how they had taken her in as a partner while being the killers all this time, and how they had been the one who killed her son. She will announce that she feels nothing but contempt for Scott and Rae before spitting on their graves and walking away. If Lauren is dead, the camera will pan on the grave of Scott's brother and Rae's friend, John Sheppard before panning dramatically around Scott's and Rae's graves.