The Sanctuary's Flying Stairway has 11 aluminum steps. In Seasons 2 & 3, the stairs were padded with black rubber so the actors wouldn't fall. The rubber also muffled the actors's footsteps so that they could perform dialogue without having to edit it in the Sound Room.
Season One featured a Virtual Dojo where the Mutant X members would have simulated battles. After Genomex's demise, the Virtual Dojo was removed for the remainder of the series. It was replaced by a sitting room with two desktop computer consoles.
In Season One, Adam's Lab featured a raised Plexiglas floor which had a black scan chair in the center. For the remainder of the series, the floor was changed to a flat black tile floor and the chair disappeared. This made it easier for sound issues and for actors and crew to move around.