In the Emergency Room, the dead patient's eyes and head change positions between the time Mrs. Cushing and Dr. Spezio look at him.
Diana Rigg says that she lived for a year with the Hopi Indians - but she mispronounces "Hopi" as "Ho-pye."
About 10 minutes into the movie, as the characters walk down a hospital hallway, followed by the camera, a technician and his microphone are revealed behind a nurse's cart. The camera then tightens the shot around the actors.