Conversation between Ziva & Tony at episode start: "Never be unreachable." "Rule number three." However, in S1E1, Gibbs himself states to Special Agent Kate Todd: "Rule number three: Don't believe what you're told. Double check."
When McGee shows up for work in a turtleneck shirt, Tony refers to him as "the ghost of David Niven." Tony later tells Ziva he used the "genital cuffs" gag from the movie Dirty Rotten Scoundrels (1988) to get some information from two teens. The movie Dirty Rotten Scoundrels was a remake of the movie Bedtime Story (1964), which starred David Niven (in the role later played by Michael Caine).
Zac Efron, who guest stars in this episode, played Ted Bundy in Extremely Wicked, Shockingly Evil and Vile (2019). Mark Harmon played him in the film The Deliberate Stranger (1986).
When McGee shows up in the turtleneck outfit, among the ways Tony mocks him is to call him Banacek (pronounced BAN-a-check.) Banacek (1972) was a 1970's series starring George Peppard as a suave, urbane insurance investigator. Based in Boston, he favored turtleneck sweaters and drove a 1940 Packard. Banacek was rotated on the regular schedule with Colombo, McCloud, and McMillan & Wife, although it ran for the shortest time, only two seasons.