The different colored uniforms worn by Clockworks Psychiatric Hospital patients are to classify a patient's level of risk of violence. Patients who wear white uniforms are of no risk of violence, yellow uniforms have a mild to moderate risk of violence, and red uniforms are of a high risk of violence.
Charles Xavier's voice can be heard in the background swirl of voices, early in the episode, but Patrick Stewart does not have an acting credit for the episode.
Several characters refer to an "incident at Red Hook." Red Hook is the name of the town next to Bard College, where Marvel character Jean Grey was buried. Jean Grey's father was a professor at Bard College and Jean Grey grew up in the area.
To depict David Haller losing control of his abilities in a kitchen, actor Dan Stevens was filmed separately from the practical effects, with the images layered together to create the final, slow-motion sequence.
The mental institution David, Lenny, and Syd are in is called Clockworks Psychiatric Hospital. This is a reference to Stanley Kubrick's movie, "A Clockwork Orange," which the creator of the show, Noah Hawley, has said to have taken great inspiration from. As with the name of the institution, most of the patients can be seen in orange outfits, which also references the movie.