I Don't Know
Before Spock departs for Earth, there is one peculiarity in Amanda's goodbye.
"Oh; one more thing. Sometimes, humans say 'I don't know', and leave you to make decisions for them. But, that sentence still contains a clear answer. 'No.' You have to honour that."
He didn't understand what she meant until now.
I Don't, No
When Spock enters The Captain's quarters, he is facedown, his face buried in the pillows. He has clearly forgotten about the chess game they arranged for after their shift.
"Do you require assistance?" Spock asks.
"I don't know," Kirk replies; muffled by the pillows. It could just as easily be: "I don't; no."
Spock leaves the room.
I Do Know
But, life, like chess, is a sort of dance. A series of carefully planned missteps and stumbles. After all: they say that walking is just a sequence of controlled falls, and each step returns him to where he began.
When Spock returns, Jim's question is garbled. The man is buried under blankets by now, but a hand emerges from the covers and gives him a tired wave.
"What do you want, Spock?"
"I do not know."
But, he does.
There are countless ways to mishear one another- in life, but particularly on a starship. Misinterpretations.
The hum of the engines can follow you anywhere. Even when you're not aware of it, it's still there, in the background. Unspoken.
How Spock came to be curled up with in the Captain's bed, I'm sure you can guess. Perhaps there was a certain logic to it.
Perhaps there wasn't, and that's why he felt the urge to go.
Before Spock departs for Gol, there is one peculiarity in Jim's... Closing statement.
He doesn't plan to return.
But life, like chess, has a sort of pattern to it.