A lot of key elements in the unsubs' backgrounds are similar to Oliver Stone's controversial Natural Born Killers (1994). The movie followed a murderous couple on a killing spree. One key element from the movie is Mallory attacking anyone that comes on to her in a sexual manner. Both elements are incorporated into the episode. And just like Mickey calling Mallory "Mal," Ray calls Sydney "Syd". The film Natural Born Killers is based loosely on Charles Starkweather and Caril Ann Fugate.
The episode is titled "The thirteenth step" which, coincidentally, was the 13th episode of the season.
"Thirteenth-stepping" is a derogatory term for Alcoholics Anonymous members approaching new members for dates or sex. AA's pamphlet on sponsorship suggests that men be sponsored by men and women be sponsored by women. This also happens to be the thirteenth episode of the sixth season.
Adrianne Palicki is one of three recurring actors on The Orville (2017) who play unsubs. Chad L. Coleman plays an abusive husband in Season 7. Scott Grimes shows up in Season 8 as a nurse killer.
Jonathan Tucker and Adrianne Palicki portray lovers. Adrianne Palicki starred as Tyra in Friday Night Lights (2006) alongside Matt Lauria. Matt Lauria and Jonathan Tucker both starred in Kingdom (2014).