Kill Switch - S5-E11
Continuity mistake: In the same season episode "Unusual Supects" Fox Mulder's file lists him as Fox William Mulder. The A.I. discovers a similar file but the name is just Fox Mulder.
Visible crew/equipment: I don't know if this is visible in all formats, but on the newest UK release on DVD, watching in widescreen, it's amazingly obvious. When Mulder recovers from the vampire attack, he gets up from the floor and breaks up a chair to make a stake. There is a shot of his feet as he smashes the legs off and bends to pick up a piece. In the bottom left hand corner of the screen, you can see a crew member's hand carefully and quickly placing a piece of wood on top of the pile for Mulder to pick up.
Revealing mistake: When the doctor examine Ronnie's "corpse" in the morgue, he pulls out the stake. It is quite obvious that he's struggling with a wooden stake that is placed on the actor's side, not through his chest. Moreover, the camera pans up and you can briefly see Ronnie's unharmed chest.
Continuity mistake: In season 2's "Ascension," Skyland Mountain was a private ski resort, yet here we are told it is a national park. (00:25:10)
Continuity mistake: Uroff-Koltoff Star of Russia in New York Harbor is a completely different ship from Uroff-Koltoff Star of Russia leaving Vladivostok at 17:45. (00:33:10)
The Red and the Black (2) - S5-E14
Revealing mistake: It seems that in the first shot the doctor injects something into the vaccine vial rather than extracting from it since the syringe plunger is moving inwards instead of outwards. In the next shot one can see that the syringe is being filled with the vaccine, however the arrangement of doctor's fingers is suitable for injection, which strongly suggests that the scene is played backwards. (00:17:55)
The Red and the Black (2) - S5-E14
Continuity mistake: While in the car with Scully, Mulder turns his head aside of Scully towards the side window twice: once when the shot is facing Scully, and just after in the shot facing him. (00:40:25)
Character mistake: While examining Agent Michel's body, the doctor says to Arthur Dales about "toxology report" instead of "toxicology report." Toxology is the study of archery. (00:26:50)
Mind's Eye - S5-E16
Other mistake: Since the apartment was supposedly "turned inside out and upside down, " as Detective Pennock claims, it would be practically impossible that such an obvious place as the shaving blades container not be dug up thoroughly by the police. (00:12:15)
Mind's Eye - S5-E16
Continuity mistake: When the policeman passes the phone over to Marty, in the first shot from behind she holds it with two hands, while in the next frontal shot she grabs it with her left hand and then with the right hand. (00:13:20)
Mind's Eye - S5-E16
Visible crew/equipment: During the scene of Marty's interrogation there is some dark blue element behind Mulder when he is reflected in the mirror. However, in the frontal scene there is just a plain wall behind him. (00:24:00)
Mind's Eye - S5-E16
Continuity mistake: While talking through the jail glass, Marty's face is generally directed straight toward Mulder's face when reflected in the glass, but her head is twisted to the right when filmed from Mulder's side. (00:34:40)
Mind's Eye - S5-E16
Continuity mistake: At The End of this episode when Mulder is talking to Marty through her jail cell, the position of their hands change. In one shot, Mulder's hand is covering hers, and in the next, each of their hands are gripping the cell bars. This goes back and forth a few times. (00:43:00)
Mind's Eye - S5-E16
Other mistake: When Marty is being transferred and 'sees' herself because the killer is watching her, she should have seen herself viewed through a wire fence, as the killer was standing behind one.
Continuity mistake: If the Kernoffs were really devoted Catholics why would they have waited six years to have Dara baptised? (00:00:40)
Continuity mistake: When Dara walks toward the angel, there is only one car, parked on the right side of the street, but when her father approaches her, there is another car parked on the opposite side of the street. (00:02:50)
Revealing mistake: During the autopsy, right after Scully has the vision of her daughter, the body of Paula Koklos can be seen to move (watch her hands and neck). (00:24:05)
Answer: As he stated many times throughout the series, Mulder needed Scully to be sober and skeptical. Whenever Scully's skepticism wavered and she started questioning her own rationality, Mulder would try to restore her sense of skepticism, because he needed her to be clear-thinking.
Charles Austin Miller