The pre-credit sequence features the song "Christmas in Hollis" by Run-D.M.C., which is also used in Die Hard (1988), Peralta's favorite movie.
In the cold open, Boyle claims to be 42. The actor who plays Boyle, Joe Lo Truglio, turned 43 the day before this aired.
When Charles, Holt and Jake are in the safe house, Holt says something, and Jake says "touchie" instead of "touche." Charles says that he's "heard it both ways." This is very similar to Sean Spencer on Psych (2006). He'd say he'd heard a word or phrase both ways even if he actually didn't.