Factual error: When Mulder is visited by his mother, he definitely shows brain activity, because he is "talking" with her, however there are only flat lines on the monitor. In a similar situation in "The Sixth Extinction" episode, when Kritschgau and Skinner ask him questions and he anticipates them, the monitor shows intensive bursts.
Factual error: When Skinner is at Kritschgau's apartment building, the time stamp onscreen says it's 5:05 AM, but when Kritschgau answers his door, he says it's 6:00 in the morning. Plus it is shown to be broad daylight outside. The sun is never up that early in Washington, D.C.