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: When Mulder and Scully are going to the caravan for the first time, you can see a person walking in the background, but when the shot changes they are no longer there. (00:17:05)
Continuity mistake: Just before he removes it, the foil disappears from Ray's sandwich in one shot, then appears again in the next shot.
Factual error: Scully makes a reference to an F.B.I. field office in Kansas City, however, no such office existed at the time of this episode. (00:13:10)
Revelations - S3-E11
Factual error: After the agents meet with Kevin's father in the mental institute, Scully lists the medication that he is on: haloperidol, loxapine, and chlorpromazine make sense, but the fourth medication - LARGACTIL - is in error. Not only is it a brand-name of chlorpromazine, but it is not available in the USA, it is a CANADIAN drug. (00:36:10)
Continuity mistake: We see Cindy and Teena at the table talking with Eve 7, drinking out of paper cups. Later on, when Mulder picks up a cup from the table, it's made of glass. (00:30:40 - 00:34:30)
Continuity mistake: When Max is trying to escape through Mulder's window, in the first shot, the bottom window is halfway down, but in the next shot, it's fully up. (00:15:35)
Visible crew/equipment: When Scully asks Fox "Do you know what day it is?" the boom mic drops down at the top of the screen. (00:04:50)
The Pine Bluff Variant - S5-E18
Continuity mistake: When the bank manager goes to open the door for the brinks truck containing the robbers, the clock on the wall reads 9:45. When the robbers are taking him back to the vault, a couple of shots of the skull-masked robber shows the clock reading about 9:43.
Factual error: Mulder mentions the USS Eldridge as disappearing from Philadelphia (and later reappearing in Norfolk) "nine months after Roswell", i.e., May 1948. In fact, the supposed incident took place much earlier - in February 1943, according to almost all reliable sources. (00:06:50)
Continuity mistake: When Scully and Mulder first visit John Mostow he says that he drew all the pictures of Gargoyles, which would have been a pretty good act considering he was in a strait jacket and would not have been allowed to have paper and drawing materials anyway. (00:07:30)
Continuity mistake: When the dad is offering the son some ice cream, the cone he offers is a single scoop. In the next shot, as the son takes it, it is now a double scoop. In addition, the scoops change from single to double and back and forth in the next few shots.
Visible crew/equipment: When Scully asks Mulder, "Are you losing it?" the boom mic is at the top of the screen. (00:23:20)
Continuity mistake: In the shot of the 6th Precinct police station, it has a California state flag flying out front. The episode took place in Massachusetts, at the Massachusetts Institute of Technology. (00:07:45)
Visible crew/equipment: When the Lone Gunmen catch up with Suzanne at The End of the episode, when she is talking to them and the camera is on the three, you can see not one, but two boom mics at the top of the screen. (00:40:20)
Schizogeny - S5-E9
Continuity mistake: After her father is pulled out of the window, Lisa leans out and there is no glass left on the sill, she even places her hands on it. Later when Mulder and Scully look at it, there is all sorts of jagged edges on the sill. (00:16:35 - 00:20:00)
Fresh Bones - S2-E15
Revealing mistake: While Mulder, Scully, and the groundskeeper are walking through Folkstone Municipal Cemetery, there is a partially hidden but still conspicuous sign that reads "Vancouver Cemetery." (00:18:45)
Continuity mistake: When Fox Mulder is having the flashback when Samantha was abducted, he looks at the doorknob, in the close-up he is still looking at the doorknob but it has changed colour.
Continuity mistake: Scully's FBI badge number that she gives to the phone company is different to the one she gives in season 4's "Teliko". (00:02:05)
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