Jonathan Nolan, executive producer and creator, and Greg Plageman, executive producer, are shown in the final scene, as hospital orderlies.
When John Reese informed Sameen Shaw about The Machine, the color of rectangular indicator on her face became yellow, which was previously of indigo color, given that she was affiliated with Indigo division of the Control. But once she was informed of the machine, it changed its identification color for her, making her upgrade on the level same as John, Finch and Root, who have same yellow identification rectangle indicator on their face in The Machine's camera.
A character, Lawrence Szilard, is a reference to a physicist Leo Szilard.
The park where Reese and Finch walk their dog at the end of the episode is in downtown Portland.