 PLOT: SPOILER: When Deckard arrives home, Rachel is already waiting  for him in the elevator. However, a) Rachel has no way of knowing  where Deckard lives, as information regarding a policemans address  is not given out to the public, least of all a replicant, and b)  Rachel could not have followed him because Deckard was first taken  by Gaff to Leons apartment via police spinner, then Deckard drove  home using his own sedan; and even after driving home, Rachel was  already waiting for him.