In the scene where Diggle and Roy drink in the name of Oliver, Diggle uses the word "Prochnost" which in Russian means strength, durability, stability, toughness, solidity and endurance.
This episode marks the first time Arsenal is called the Red Arrow.
When Captain Lance refuses to take his police out of an entire district of the city, Brick replies, "They did it in LA in '92." This refers to the Rodney King Riots, where the acquittal of four policemen after their videotaped arrest and beating of a taxi driver (King) led to riots lasting more than six days over a widespread area of Los Angeles. While the police did not actually cede control to the rioters, they were unable to control the situation themselves and the National Guard had to be called in.
Palmer says helicopters don't have keys, but this isn't exactly true. Historically they did not, and not all do; but the US Army in 1974 began requiring keys because someone took one without authorization. Even if they don't have an ignition key, many have door keys.
When Merlyn visits Thea at her apartment, she is reading The 5th Assassin by Brad Meltzer (appropriate, given their enemy is the League of Assassins). Meltzer also writes comic books--his first effort was the 2002 Green Arrow story, Archer's Quest.