Goof: When Porthos licks the comatose Archer's face, Scott Bakula winces before the camera angle changes.
Nitpick: There is no apparent reason for Phlox to wander the corridors with the lights off, using a flashlight, other than to create the frightening setting.
Trivia: The movie Phlox watches in the episode is 1956's The Court Jester.
Trip: No offense, Doc, but under normal circumstances I wouldn't even let you in here without four years of Starfleet training under your belt.
Phlox: These are hardly normal circumstances.
Phlox: On your worst day you're more qualified to operate the warp engines then I am!
T'Pol: Unfortunately this is by far one of my worst days.
Phlox: I should never have let Mr Tucker talk me into watching The Exorcist last week.
Phlox: I'm a physician, not an engineer!
This episode shares a similar plot to the Star Trek: Voyager episode "One", where the crew have to go into stasis to survive the journey through a nebula, leaving only one crewmember unfamiliar with solitude to ensure the ship makes it through safely.
John Billingsley apparently does a nude scene. According to a UPN source talking to Sci Fi Wire, this was partly the result of production calling Billingsley's bluff.
Phlox: I'm a physician, not an engineer.
This is an homage to Dr. McCoy's signature line in The Original Series.