Topher and Ivy are programming the actives back to their original personalities in one scene. The active in the chair is Gary, played by Rick Fox who, at the time of filming, was in a relationship with the top billed actress on the show, Eliza Dushku.
When Echo discovers a file on Bennett Halverson, she comments that Bennett is "off-the-charts smart," adding, "I bet you could kill me with your brain." Bennett is played by Summer Glau, who in Joss Whedon's previous series, Firefly (2002), played River Tam, a psychic super-genius who once advised another character, "I can kill you with my brain." River's amygdala (part of the brain) was damaged by experiments, and Bennett says "I'd love to get a look at your [Caroline's] amygdala."
Olivia Williams (Adelle DeWitt) and Rhashan Stone (Test Subject) are married in real-life and have two children together.