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."
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 is in a relationship with the top billed actress on the show, Eliza Dushku.