The Silence of the Lambs(1991)
Dr. Chilton is the physical manifestation of Hannibal's oldest , innermost demon; the one who keeps him a prisoner in the dark recesses of his mind , he is the representation of the cold blooded reptile within Hannibal or his reptilian brain . ...

The reptilian brain is the oldest most primitive part of the brain . Most responsible for aggression, dominance, territoriality, ritual displays, feeding, fighting, fleeing, as well as… the other F .Notable behavior patterns include defense of self, family, and personal property, physical communication, and socially approved actions.

Chilton's first statement : Do you still think your gonna WALK on some beach and see the BIRDIES-I don't think so..."-Chilton
tells Hannibal , your will not evolve/ progress or escape me/this state of mind ..

Chilton is very very aggressive ,He wears scale like suits (earthy tones )and speaks breathy and snake like.When Hannibal gets mad he hisses " I ate his liver with some fava beans etc ... ":P:P:P:P

-Dr. Lector himself is the representation of the ego-destructive superego .Hannibal just wants a room with a view and trees .(within the cerebrum ;at some point between the frontal & occipital lobes ; higher thinking art logic etc ) far away from Chilton ; Hannibal as a medical professional knows his problem, Chilton ..As the representation of ego-destructive superego.He wants to destroy Chilton..

Because they are both one in the same and separate ;they never directly touch. .

Hannibal is trapped locked in a upright position . The reptilian brain controls balance breathing etc.His focus is on the Pen (The Pen is gold like that of a key)--The pen represents the mammalian/paleomammalian brain.. .It evaluates everything as either agreeable (pleasure) or disagreeable (pain/distress)and takes function to higher or lower level based on the judgement.As Chilton is no longer visible but we can hear him .Things are unfolding --- Hannibal angry of the news of the fake deal doesn't focus on Chilton and rage out ,but rather the Pen .Hannibal is judging the anger as useful and begins devising a devious plan (using the key ; communication/lying)..When Chilton finally gets an answer he smiles.Hannibal gave into Anger when responding to Chilton.. Than Hannibal mentions he has some terms of "HIS OWN" Chilton raises a eyebrow ---Hannibal thinks of the results of his terms (involve happier higher thinking) . Chilton then quickly leaves because they are out of his realm .. ..As he leaves he tells Barney to clean him UP get him ready to go..

-Barney is a representation of the inner voice/spirit(C+H).

--The whole film can be seen as a psychoanalytic examination of the philosophical book/question -Beyond good and Evil .(Friedrich Nietzsche)
The film ask the questions ;What is beyond good and evil and how does it get there ?
Example shown in the film the - Death's-Head Hawkmoth:
It burrows and kills in order to change ;Is it good or evil ,what happens after it changes ?etc..

Spoiler ALERT
As Lector arrives at the airport Chilton is there too(surprise) and Lector declares he will have an old friend for dinner .. As the representation of ego-destructive superego. it is Lector's intention to destroy Chilton to be finally and completely free and at peace.