at this point they've figured out that Giant Electric Ball has been keeping Space Explorer Dude as her lover all these years. SED's all like, huh?
For 150 years, she's been doing the Electric Boogaloo with you, Spock explains. "I do not totally understand the emotion, but it obviously exists."
SED is totally horrified by this. "But it's alien!" he exclaims. "For all these years I was letting an alien get it on with me?!"
Spock is looking rigidly at Kirk here. Kirk just shoots him this intense expression in response that somehow manages to be two parts "I apologize to you on behalf of my race, and I'm sorry you are having to hear this", and at least one part, "You know how much you mean to me, right?"
To SED he's like, "Look, she saved your life, what's your problem?"
"It's DISGUSTING!" exclaims SED. And this is actually a really daring ep for them to broadcast during the era, because our Fearless Trio's response to this is, emphatically:
"There's nothing disgusting about it. It's just another life form, that's all!" I really love Bones and his constant sense of right and moral indignation.
Spock adds that SED has been quite cozy with his Electric Youth for 150 years, and clearly has been quite happy - so why freak out now that he knows he's been getting companionable with a female ball of light? ('but i didn't know it was a woman!')
"Do people in the future have no sense of decency or morality?" exclaims SED in shock.
And then the camera cuts to Kirk. Who is now just sitting there like this.
Now, I think there are a lot of ways you can read this kind of body language, but in James T. Kirk it's a bit startling, because usually Kirk's anger and indignation take the form of outward gestures - thrust chest and lifted head, defiant eye contact. This is, however, a completely inward, self-reflexive expression. And he doesn't even respond. He just sits there with his shoulders hunched. Like this particular argument is such a personal affront that he can no longer bear looking its proponent in the face.
SED leaves with an angry comment about inhuman monsters.
Spock's just like, "wow, a totally parochial attitude! this will make a great addition to my data on primitive societies and the life forms who inhabit them!"
Kirk laughs a sad, odd laugh, and still doesn't reply.
Then Kirk decides to interview the Giant Electric Ball.
"Do you love him?" he asks GEB, who's like, I'm sorry, could you repeat the question?
Is he important to you? Kirk asks. More important than anything? Then, still trying to find words, he settles on:
"Does he feel..... as though he were a part of you?"
GEB responds, yes, he does, and they bicker back and forth about her refusal to let them all off the planet. Finally, Kirk insists:
"But you can't really love him. You haven't the slightest knowledge of love: the total union of two people. You are the Companion, he is the Man - you are two different things!"
"You can't join," he says. "You can't love." And the look on his face is one almost of utter sympathy - or maybe even, perhaps, fear that in addressing the Companion, he is really addressing himself.
So then GEB freaks out and is like, "But if I were human, there would be love!" and vanishes.
Doc: Way to go, Jim.
Kirk: I thought if pressured, she'd try to sacrifice herself and let us go.
Spock: Your notions of love have been distorted by the fact that you would do anything for me and I for you. It is not logical for all life forms to react this way.
(......But he seems to cheer up rapidly after that. )