"Black Thorine", the deadly chemical Sydney and Nadia go after, is named after Donald E. Thorine jr., director of photography of this episode.
When Sydney is confronting Sloane after she and Nadia are reprimanded, she says she doesn't like that she has to pretend that the past three years didn't happen, but technically at this point, with the two-year flash forward in season three, it's been five years.
This was originally the 4th episode of the season. This episode averaged 10.48 million viewers.