The character John Dee shares his name with an infamous Elizabethan astrologer and occultist, and is also a character carried over from the Justice League and Swamp Thing comics.
The episode adapts issues #6 and #7 from the comic series, "24 Hours" and "Sound and Fury". The episode title, "24/7", reflects this in the name.
The music playing as John Dee enters the diner is from Mozart's The Marriage of Figaro, coincidentally the same as played by Andy Dufresne in The Shawshank Redemption.