First use of "title of [your, Amy's] sex tape by Peralta to Santiago, total of 3 times in the episode: 1) "Kind, sober, and fully dressed." 2) "I'm sorry about tonight." & 3) "It's not your fault, I was terrible."
The safe number was 3109.
Near the end of the episode when everyone dresses up in Halloween costumes to make Boyle feel better, Rosa is dressed as the Bride of Frankenstein. However, if you pay close attention to her neck, Rosa doesn't have the bolts in her neck traditionally associated with the Frankenstein monster. Instead, her bolts are actually shotgun shells.
Gina and Jake have a friend named Natasha whose dog has lupus. Canis lupus is the scientific term for wolves, which are of the same genus (Canis) as dogs.