Other mistake: Larina dials 4, 1, and 4, but the voice in the phone says, "This is operator 525." (00:23:25)
Continuity mistake: When Ray is eating the sandwich, there is a large bite out of one corner just before he removes the foil. In the shot from behind after the foil is removed, the bite is only from one slice of the bread.
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: Dogget says that "It would require something 4,300 times the density of steel to cause this damage." Steel is about 8 times denser than human flesh, so bearing in mind that density is proportional to mass at constant volume, it means that Ray would be 4,300 x 8 = 34,400 times heavier than if he were a regular human being. Assuming that he normally weighed about 80 kg, after the transformation he would weigh 80 kg x 34,400 = 2,752 tons. It means that hardly any ground would support his incredibly huge mass, let alone items such as a bed, chair, stairs, building structures, etc.
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