Colony (1) - S2-E16
Continuity mistake: When the doctor leaves the common room, he is holding a chart in his left hand, but when he is running down the corridor, both his hands are free. (00:04:40)
Continuity mistake: When we see Dana Scully after being abducted she has an instrument in the middle of her stomach, inflating it. When we see it in the first shot there is nothing but the instrument, then in the next shot there are gauze pads taped down all around it.
Visible crew/equipment: When Mulder and Scully are talking to the owner of the trailer park and he is berating Mulder, you can see the edge of the lens in the upper left corner of one shot. This is because the lens used was of a wide angle almost fish-eye type and the edge of the lens itself can occasionally creep into the frame on most cameras.
Visible crew/equipment: Near The Beginning, Mulder, Scully, and another man are walking through a graveyard. The camera is following them to the right passing head stones. The crew can be seen reflected in a black shiny head stone as the camera passes.
Red Museum - S2-E10
Continuity mistake: Scully is walking down the steps as Mulder and the sheriff are talking about the boy. In the wide shot she is halfway down. In the closeup she comes up from behind Mulder.
Revealing mistake: The answering machine at The End appears to not be plugged into any phone line. The shot shows the phone jacks on the right side of the machine are empty. In order for an answering machine to work at least one of those ports would need to be hooked to the phone.
Die Hand die Verletzt - S2-E14
Continuity mistake: Having finished his conversation with Scully by the tree stump, Mulder walks away. However, in the next shot he again starts to walk away from Scully and from closer than before. (00:07:30)
Factual error: In the opening sequence, we see a nuclear attack submarine beneath the ice in the Arctic Ocean. When the captain orders the ship to surface, one of the crewmen mutters, "Surface to what? We're under 32 feet of glacial ice!" Except that they're not under "glacial ice," they're under Arctic sea ice, which ranges from about 6 feet thick in the summer to about 15 feet thick in the winter.
Continuity mistake: When Mulder is talking to Dana's mom about finding her cross (necklace) in the trunk, Scully's mom says that she gave it to her on her 15th birthday, but in Season 5 in Christmas Carol, Scully has a flashback to receiving it at Christmas. (00:41:40 - 00:43:55)
Soft Light - S2-E23
Factual error: Dr Banton's shadow devours the second policeman, however Banton cannot cast a shadow in that direction. (00:11:35)
Soft Light - S2-E23
Continuity mistake: When the guy looks through the peephole, Dr Banton casts no shadow, while in other scenes he does. (00:01:55)
Soft Light - S2-E23
Revealing mistake: When taking a closer look at the doors of the hotel and the people entering it at the start, it can be easily noticed that this scene is played backwards. (00:00:05)
Continuity mistake: When Scully starts the procedure of taking out the bug from the body, she is wearing no mask, but when she finishes it she is wearing the mask. (00:21:45)
Visible crew/equipment: When Mulder climbs up the tower of the submarine, his shadow is visible, projected on a studio wall. (00:32:40)
Fresh Bones - S2-E15
Continuity mistake: In one shot near the start the private is turning the steering wheel while in the previous and next shot he holds the wheel fast with his arms outstretched. (00:02:30)
Die Hand die Verletzt - S2-E14
Factual error: The loss of blood Shannon suffered was definitely insufficient to be the cause of her death. (00:25:00)
One Breath - S2-E8
Continuity mistake: When Mulder is running through the corridor, in the front shot the rack is missing and the person on the wheelchair suddenly appears, compared to the back shot. (00:14:00)
Red Museum - S2-E10
Continuity mistake: While talking, Mulder, Scully and the old farmer are leaning against the bar which is absent in the distant shot. (00:23:00)
Continuity mistake: The Father is standing in some darkened part of the room, however in the next shot the room is all lit up and there is no darkened place there. (00:38:25)
Other mistake: An agent and Scully analyze the fragment taken out from Duane Berry's body. The agent draws Scully's attention to "small markings", which are half a monitor size, and Scully naively asks where they are. (00:39:00)
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