When Emma, Mary Margaret, David, Leroy, Ruby and Doctor Whale gather in the supply room, of the hospital, the room number beside the door is R2-42. The fourth letter of the alphabet is D, which would make the number R2-D2. This coincides with the moment Greg Mendell's cell phone rings, his ringtone is the main theme of Star Wars.
In late 2012, Disney acquired Lucasfilm. The episode was filmed shortly thereafter, using Star Wars references (the cell phone ring and the room number).
When giving interviews about their most difficult scene, Colin O'Donoghue said that the scene after he gets hit with the car was the most challenging because when Gold was beating him up Robert Carlyle accidentally kicked him in a very sensitive area.
This features Dr. Frankenstein, known in Storybrooke as Dr. Whale; this may be in reference to James Whale, director of Frankenstein (1931) and Bride of Frankenstein (1935).