Ethan Rayne, played by Robin Sachs (d. 2013), was a recurring human villain in Buffy the Vampire Slayer in Seasons 2-4. In his final appearance in A New Man (S4E12, January 2000), when Buffy captures him after his latest round of malevolence, he taunts her by reminding her that the Slayer is not allowed to kill humans. He doesn’t realize that the Slayer has become ensnared in the national security state, personified by Riley (played by Marc Blucas), her new significant other and a high ranking officer in the Initiative, a secret project which, we learn later in the season, is developing a part-demon parts, part-machine, part-human super soldier.
Riley orders soldiers of the Initiative to take custody of Rayne and informs those present that his status is to be determined and he’ll be detained in a secret detention facility in a desert in Nevada. (Note: Riley is awful at keeping secrets.)
Watching this in 2019, eighteen years into the Global War on Terror and all its variants, we know that the United States and its allies operate secret torture detention facilities and one well-known indefinite detention facility at Guantanamo Bay in Cuba. A throwaway line at the end of an otherwise unmemorable Young Adult drama series episode appears in an entirely new light.