Unrequited - S4-E16
Factual error: By its uniforms, rank insignia (i.e. point-down chevrons), drill and instrumentation (e.g. tubas instead of sousaphones), the military band performing at the re-dedication ceremony at the Vietnam War memorial in Washington is a Commonwealth (probably Canadian) band and not an American band. Unlikely at a formal military ceremony in the United States.
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