The trivia item below may give away important plot points.
The closing scenes of Pilot are almost identical to the closing scenes of the season finale, The X-Files: The Erlenmeyer Flask (1994). Scully is in bed and sees her digital clock turn from 11:21 to 11:22. Mulder calls and they talk. The scene cuts to The Cigarette Man, who places an object in the vast Pentagon vault. Both episodes end with the door of the vault slamming shut and the camera showing the sign on the door: "In Case Of Fire Or Emergency / Know Your Exits / PENTAGON / Evacuation Procedure."