Visible crew/equipment: When Mulder and Scully enter the abandoned mine through a doorway, the viewer can see at right in the distance a number of people sitting on a wall, and one crouching in front of the wall with what looks like a dog. They are sitting still, but there is still movement there.
Continuity mistake: When Mulder experiences his near-death trance state his body is lying, apparently lifeless, in a star spangled sky. As the camera tracks in on him the toes on his right foot twitch, just after Deep Throat begins to speak. The foliage covering his chest also changes position between shots. In the wide shot he is covered up to the armpits. But the first close up shows his chest is exposed. Then in later close ups it is covered again.
Continuity mistake: When Skinner walks into the cafe (the time he gets shot) another man is just walking out, leaving a table with a used glass and coffee cup. The waitress is in the back, getting Skinner a cup of coffee (she couldn't have cleaned the other table yet), but when we look over Skinner's shoulder you can see that the other table is cleared and has a clean coffee cup (turned upside down) on it.
Factual error: In the scene where Mulder, the police officer and the doctor are in the doctor's room, the time on the clock reads 8:40. The doctor announces that he going to the bathroom. The scene cuts to him in the bathroom and then back to the doctor's office with Mulder and the police officer. Another cop comes in and says, "Come to the bathroom, something's happened." The clock still reads 8:40.
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.
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.
Continuity mistake: When Senator Richard Matheson tells Mulder about the four Japanese Nationals had been murdered, he says that the murders had occurred several weeks ago. But when Mulder brings Scully up to speed a scene or two later, he tells her that someone must have been able to identify the four doctors who were performing the autopsy because they were murdered YESTERDAY.
Continuity mistake: In the mine with the medical records we see Samantha's file. In the season 1 episode "Conduit" we see the X-File Mulder opened on her. In the previous episode she is listed as Samantha T. Mulder and her birth date is 1/22/64. Here we see her name as Samantha Ann Mulder and her birth date as 11/21/65.
Other mistake: After AD Skinner is finished being interviewed by the police, Mulder asks him about why he would employ the services of a prostitute. Skinner looks at him in shock and Mulder says "You didn't know she was a prostitute did you?" I find it hard to believe that at no point in the interview did the police not mention to Skinner the dead woman he woke up next to after spending the night with her was a prostitute.
Plot hole: When Mulder and Scully are going to the town/city where the disappearances took place Scully says they should stop so she can walk the dog. Mulder says OK because he has to ask for directions yet the next scene we see is Mulder and Scully interviewing Dr. Faraday. How did they find him if they didn't know where they were?. And after that we see them at a store where they do ask for directions.
Plot hole: Mulder is pulled from the escape hole previously dug by the hybrid aliens to escape the train car. When they pull him out they show alien bodies remaining in the hole. Mulder never revisits the train car despite knowing there's a high probability of finding hard evidence, in this case some actual bodies. There's no way Mulder would just assume there's no evidence remaining there and not go have a look for himself. Same goes for Cancerman who thought he had destroyed the evidence.
Continuity mistake: Later in the episode a man bangs on an air conditioner to try and stop it from making noise. In the first scene you can tell air is moving because the streamers are moving. After he bangs on the unit the streamers stop moving. The air conditioner is still on.
Factual error: At the beginning of the "Musings of a Cigarette-Smoking Man" episode Frohike says that the CSM appears when Trotsky was assassinated, i.e. 20 August 1940, but he does not claim that this is an exact date of birth. However, he further says that during the Nazi-Soviet Pact (1939-41) the CSM's father "kept NKVD informed on American plans to enter World War II" and for this reason he was executed before the CSM learned to walk. This means that his father could not have been executed earlier than in 1941. Assuming that babies learn to walk between a few months and 2 years, the CSM could not have been born earlier than in 1939. It means that in 1953 he should have been a young teenager, and not an adult man, as he is presented.
Revealing mistake: In the opening sequence, a man who is hallucinating badly is apprehended by the police. They find a dead blonde woman in the trunk of the man's car. In a close-up of the dead woman, all the dried blood on her face is an added digital effect; however, the dried blood "drifts" around, seemingly out-of-sync with the video. Similar "drifting" digital effect problems are seen in other X-Files episodes.
Add timeCharles Austin Miller
Revealing mistake: As Dana Scully is examining the dead woman found in bed with Skinner, she observes a strange luminescent glow on the woman's nose and lips. It's apparent that this glow was added digitally; but the digital effect is "drifting" around the dead woman's face, seemingly out of sync with the video. Similar "drifting" digital effect problems are seen in other X-Files episodes.
Add timeCharles Austin Miller
Continuity mistake: Clyde Bruckman commits suicide by placing a plastic bag over his head until he asphyxiates. However, when Mulder and Scully first discover him you can see in the shot just before Scully holds his hands that there is no plastic bag around his head (may only be visible in widescreen format).
Visible crew/equipment: As the camera flies over the train, in the upper right corner of the screen there is some equipment and umbrella visible that are not likely to just be in the middle of nowhere - probably filming equipment. In the next shot they are gone.
Other mistake: It seems that the first round fired by the hit squad destroys the camera or its power supply unit, because the satellite transmission is interrupted exactly at the moment the squad enters the train car. However, the members of the squad firstly shoot in the glass and then at the doctors.
Factual error: Mulder tells Scully that he is trying 27828 and it is not working. It is not surprising that it is not working, because the Napier constant is not 27828, it is 271828. Plus they somehow they know how many digits from this constant should be entered on the keyboards.
Continuity mistake: Pusher loads the revolver with one bullet, leaving five chambers empty. When Mulder picks it up and points it at Pusher, the bullet can be seen in the cylinder, just to the right of the gun barrel. Later, when Mulder begins to slowly pull the trigger for the third time (aiming at Scully), we see the cylinder turn to Mulder's left. Problem is, with the bullet situated as it was when Mulder picked it up, the bullet would have moved to the barrel and been fired the first time he pulled the trigger, killing Pusher. Instead, it fires on the third pull.