Claudia Black wasn't actually wearing one of Wayne Pygram's spare costumes. However, her costume was based on the same design. For comfort, it was fitted with foam earpieces rather than the plastic ones Pygram used.
After Claudia Black had her lifecast made to create her Scorpius mask, Jim Henson's Creature Shop Creative Supervisor Dave Elsey told her that she was perhaps the only person who smiled throughout the process.
Richard Carter, who plays Ullom, had previously contributed the voice of the spying Hangi creature in Season 3's "Scratch 'n' Snff." In 1989, he worked alongside Lani Tupu (Crais and the voice of Pilot) in the marvel comic movie The Punisher.
One of the background aliens inside Ullom's spaceship is played by "Safety Bob," Farscape's on set safety supervisor, who had a great deal of fun playing an alien from time to time.
The "slug gun" was created by Dave Elsey and Jim Henson's Creature Shop when an injection mechanism was required that didn't look like a syringe. Elsey enjoyed devising something that was part biological, part mechanical.
The sequence where the Reservoir Dogs-inspired Crichton and Harvey face off was filmed in the small corridors between the stages of the Farscape studios.
Producer Andrew Prowse had wanted to bring director Geoff Bennett onboard Farscape for some time. Bennett would go on to helm three more episodes during the fourth season. Had there been a fifth season, Prowse hoped he would return.
Ricky Manning has revealed that the writers discussed a possible plotline in which the consequences of Aeryn's time as an assassin would catch up with her again, but the idea was not taken further.