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.
The X-Files (1993)
1 plot hole in The Blessing Way (2) - chronological order
Starring: Robert Patrick, David Duchovny, Annabeth Gish, Gillian Anderson, Mitch Pileggi
Clyde Bruckman's Final Repose - S3-E4
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). (00:42:55)
More quotes from The X-Files
Trivia: The Cancer Man smokes Morley cigarettes, a fake brand that has appeared in a number of TV shows and movies since the '60s.
Question: In a vast majority of the episodes, whenever Mulder and Scully investigate some mysterious or paranormal phenomenon, Mulder believes that some unknown force is responsible but Scully always has a rational explanation for what is happening. In other episodes, when Scully herself is caught up in something mysterious, she is the believer but Mulder is the skeptic. In those episodes, why would Mulder be skeptical about an unexplained phenomenon considering that he a was witness to his own sisters abduction and he saw many strange things that defied explanation while working for the F.B.I.?
Answer: A variety of reasons. Just because Scully saw something unusual does not mean that it was. Mulder always needs concrete proof before he'll believe there's some otherworldly explanation for unexplained phenomena. He's too experienced to take a novice's explanation as fact. It is also a plot by device by the writers to switch the tables on the characters to make it more interesting and to let viewers see another side of their relationship.
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