Why do Cobb and Saito change eye color in the scene where old Saito interrogates Cobb?
That's not Saito. It's Mal impersonating Saito to fool Cobb into thinking he's waking to reality. She's already performed inception on him to make him think her totem is his.
And that's not Cobb. It's Fischer impersonating Cobb in an effort to get himself and Saito out of Limbo.
Or something like that. I don't know, you tell me.
commented 2015-10-31 07:05:12 UTC
To understand what's going on, get out you clock and time the number of seconds the top spins. In the real world it twice spins for 18 seconds before toppling. At the end of the movie it spins for 33 seconds and you can hear it continue spinning as the credits scroll. So without question Cobb's still dreaming and never makes it back to see his real kids.
That explains why he spins Mal's totem in the first place. She must know about the physical properties of his totem and so he can't trust it to tell him whether he's in a dream or not. He spins her top to find out if he's in one of her dreams.
So what's really going on? The tells are in the limbo sequence with "young Cobb" and "old Saito". Old Saito's eyes are steel blue like Cobb's. But in the real world Saito's eyes are of course dark brown. So it's not old Saito - it's a forgery.
Old Saito says he's "waiting for someone" - which echoes "waiting for a train" to which "young Cobb" replies by talking about making a leap of faith. That echoes Mal's speech on the rooftop before jumping earlier in the movie.
"Young Cobb"'s eyes are weird - big and deep blue like Mal's. There's no reason to make Leo Di Caprio wear blue contact lenses except to tell us that "young Cobb" is a forgery too - Mal's forgery. Where "old Saito" is the real Cobb.
After years of softening him up in limbo Mal induces Cobb to dream he's old Saito. In this scene she's manipulating him into taking her "leap of faith" to "come back", just as she was begging him to do in the real world.
But this leap is really into the dream she's constructed. That's why at the end "James" is talking about how he's been building "a house on a cliff" while evidently living in a house on a cliff. In the forged guise of James, Mal will enjoy Cobb's affection forever.