"I can't believe he'd leave just like that, though," McCoy was saying to Kirk over a late breakfast. It was two weeks later, and it was common knowledge among the senior crew that First Officer Spock was seriously considering, and probably going to accept, the offer to be the liaison to the Medusans. "I've read about them," McCoy continued, "They've made huge advances in science and supposedly their culture and beliefs are rational, beautiful, even. Right up Spock's alley." Kirk found he didn't want to talk about it, although he allowed McCoy to, knowing that in spite of all their bickering, McCoy would miss Spock almost as much as he himself would. Spock then came into the mess, saw them, and as soon as he sat down, launched into a discussion about the Medusan advances in astrophysics.
"They appear to have made discoveries about black holes that our own equipment cannot yet measure. It will be fascinating – Captain? Is something wrong?" as Kirk suddenly got up.
"No, Mr. Spock," the captain said with a sigh, "I just have to go see who's available to take your position as First Officer, and Science Officer for that matter." Spock started to say something, but Kirk cut him off. "It's all right, Spock. Just…we will see you again, right? I'd rather lose a First Officer than a friend." The captain then left, with Spock and McCoy left sitting there.
Spock was trying to sort through his thoughts. He did want the position. The more he learned about the Medusan scientific advances and culture, the more he thought it was an opportunity he could not pass up. But what the captain said had made him think. Kirk had looked so lost, sad at the thought of replacing him, and Spock had to admit that the thought of someone else taking his place on the Enterprise was displeasing. More than it should have been. Such a reaction was illogical. A position was a position, and it was illogical to turn down such an opportunity for scientific knowledge and cultural understanding. Still, Spock could not forget the sadness in Jim's eyes, changing to a slight hope when he asked if they would be seeing Spock again.
"Spock?" McCoy's voice broke into his thoughts. "Look, I know I can't tell you what to do, and I mean, if you want to go, then who am I to stop you? But, just make sure. That it is the right thing to do." McCoy's tone was much gentler than it normally was when dealing with Spock, and that more than anything else made Spock want to bring this back onto a normal plane.
"Doctor, I must remind you that I have not given my answer yet."
McCoy bristled, "I know that, Spock. I'm just telling you; don't do something you might regret later. That's all."
"I am a Vulcan, Doctor. We do not regret."
"Hmph," was the Doctor's eloquent answer. "Sure you don't." And Spock was forced to agree, because he couldn't ignore the small twinge of regret he noticed each time he remembered how sad Jim looked when they discussed his leaving.