At the start:
A horse and a man, above, below,
One has a plan, but both must go.
Mile after mile, above, Beneath,
One has a smile, and one has teeth.
Though the man above might say “hello,”
Expect no love from the Beast Below!
At the end:
In bed above we're deep asleep
While greater love lies further deep
This dream must end, this world must know
We all depend on the beast below.
I know The Beast Below is a giant whale in the episode- but could it also be the Id? At first they are living out of kilter with it- and so it's scary and bad, but once the balance has been re-dressed and its all out in the open -they all realise they depend on it.