In a Vietnam flashback scene, Skinner is shown shooting a young Vietnamese boy who has grenades strapped to his body. Skinner recounted this story earlier in One Breath (1994) when he is trying to convince Mulder not to quit the FBI.
Sergei is Walter Skinner's middle name.
Mitch Pileggi accidentally wore his wedding ring throughout the filming of this episode. It had to be digitally removed.
The title sequence says "A war is never over" instead of "The truth is out there".