About 25 minutes into the episode, Boomer is searching for the source of a signal. She searches through and knocks over a bookshelf. Among the books on the shelves were Raise the Titanic! (1976) by Clive Cussler, Burr (1973) by Gore Vidal, Daughter of Silence (1961) by Morris L. West, The Warbirds (1990) by Richard Herman, Jr., The Final Diagnosis (1997) by James White, Puppet on a Chain (1969) by Alistair MacLean, The Burning Mountain (1983) by Alfred Coppel, The Second Seal (1950) by Dennis Wheatley, The Angry Tide (1979) by Winston Graham, The Holcroft Covenant (1978) by Robert Ludlum, a book by Doris Lessing, a book by Eric Ambler, a book titled Night Sky and a book with the word "Oberst" on it. (It is unclear whether that is the title or the author's name.) Another book, possibly a spy thriller, has a swastika on the cover.