Although credited, Sofia Vassilieva (Ariel Dubois) does not appear in this episode. She is conspicuously absent during a number of the Season 7 episodes since she was attending Columbia University in New York when they were being filmed. Within the context of the show, Ariel's absence is explained for the same reason. Incidentally, Vassilieva graduated with honors from Columbia in 2014.
Throughout the episode, whenever Allison's skin-grafted hand begins to react, "Hands All Over" by Maroon 5 plays.