DECKARD: What's that going to prove?
TYRELL: Indulge me.
I love how this film is so rich in tiny details. When Dr. Eldon Tyrell says “indulge me” he makes the sign of benediction to Deckard. It's so momentary that most people probably never notice it, even when rewatching the film. Of course it connects to the later scene when Roy Batty confronts Tyrell as his maker; Tyrell is also Rachael's maker, and, this gesture implies, Deckard's. I wonder if it was Ridley Scott's idea or just a subtle touch of the actor's own devising.