Five and Six's real identities are revealed in this episode.
Directed by Amanda Tapping, perhaps best known as Samantha Carter in every iteration of the Stargate franchise.
Arax calls 4 Ryo Tetsudo. 'Tetsudo' is Japanese for 'railroad'; tetsu is iron, do is road or method.
Nyx (when spelt nix) is another word for zero and Devon rhymes with seven.