Doors are a metaphor for Michael and Kay's relationship in the other films, too. In GFII, when Kay is visiting her kids after her split from Michael, he closes the door on her. In GFIII, in Sicily, Kay and Michael are that close to renewing their romance when Calo knocks on the door to tell Michael that Don Tomassino's been shot. Michael leaves Kay, goes through the door to do Sicilian vengeance business with Calo--as the camera pans backward on Kay, alone, on the other side of the door, with a look of resignation and regret, as if to say, "this isn't me--I'm not part of this."