In the final act, Luke expresses the hope of avoiding "another Waco". The Waco siege in 1993 was originally an operation by the Bureau of Alcohol, Tobacco, and Firearms, targeting the Branch Davidians cult in Texas, suspecting them of stockpiling illegal weapons; a planned raid turned into a two-hour firefight when their element of surprise was accidentally compromised. Taking over after the deaths of four ATF agents and six cult members, the FBI began a standoff that lasted 51 days, alternating tactics of negotiation and harassment, the goal of the latter being to drive the members out by force; on the final day, after the FBI inserted tear gas into the building, three fires broke out simultaneously and, due to strong winds, engulfed the compound, resulting in 76 more deaths. David Koresh, the cult's leader, was also, in part, a loose inspiration for Benjamin Cyrus, the cult leader from season four episode Minimal Loss (2008).
Garcia alluded to The Twilight Zone (1959) episode entitled Time Enough at Last (1959) starring Burgess Meredith (man who broke his glasses).
Directed by Aisha Tyler, the fourth series actor to sit in the director's chair. Matthew Gray Gubler, Joe Mantegna, and Thomas Gibson have all directed multiple times.
At the time of filming, the Doomsday Clock was at two and a half minutes to midnight. As of April, 2018, it had counted down to two minutes to midnight, the closest it's ever been to that point, largely due to the United States taking a reduced role in world leadership, the imminent threat of nuclear war between North Korea and the United States and climate change. The only other time the clock was this close to midnight was in 1953 when the United States and the Soviet Union began testing the first thermonuclear warheads. The council that decides the "time" the clock is set at only meets twice a year, which is why the clock's "time" never changed due to the Cuban missile crisis in 1962 since the crisis resolved itself in just a few weeks. Council members said if they had met during the event they would have set the clock at 30 seconds to midnight as that event brought the United States and the Soviet Union right to the brink of nuclear war.
As of June 2020, it is now 100 seconds to midnight, the new closest that it's ever been. This is largely due to a reduction in arms control across the globe and an insufficient response to increasingly threatened climate.