S
From Tardis Wiki, the free Doctor Who reference
As spoken by Sarah Jane Smith, S (Morse code: ...) (TV: The Man Who Never Was) was the nineteenth letter of the alphabet, following R and preceding T. (TV: The Masque of Mandragora, Goodbye, Sarah Jane Smith)
In 2012, Diana Goddard ordered that Henry van Statten be memory wiped and left on the streets in "San Diego, Seattle, Sacramento. Someplace beginning with S." (TV: Dalek)