@goldenteadust Picking up there, on the 'chasing tail' front' there is a lot of context here to consider. For a start Rayna is set up blatantly as a Spock parallel (identifies him as a kindred spirit immediately plus with the whole 'emotions' arc) - the clincher is the very end 'you don't know love [except you do]' scene that contextualizes the parallel as relating to Kirk and love - there is certainly more to this than meets the eye.
This is a season where Kirk is repeatedly coerced, drugged and sexually assaulted (and while audiences often ignore this, the character IS played on screen accurately as unhappy/conflicted during these encounters). Season 3 should really be called 'Kirk is hella traumatized'. AND all this during year #3 of...whatever his relationship is with Spock, that is growing in closeness and intensity. It's not at all hard to see Kirk at this point as someone needing help in terms of dealing with trauma (probably bottling it); combined with complicated (or maybe...simple) feelings for his closest friend who (implied by the end scene) has not thus far reciprocated in the desired fashion, and whose comfort is probably even more greatly longed for since Kirk's trauma almost all relates to abusive 'romantic' encounters - and this episode demonstrates all of this. Kirk not in a good headspace, not dealing with things well, not at all at his best - the shift of priority and single-minded desperation is really indicative of this; he's not being great at his job (and this is consistent for him - we see that in TMP, Kirk's decisions and motivations are 'off' when he's depressed...and Spock-less); he latches onto innocent, femme-Spock like a life raft and everything else goes out of the window.
McCoy's speech at the end is more poignant the more you think about it. He clarifies Kirk's desperate state, even if he doesn't acknowledge the extent to which Kirk is damaged, why he is coping SO badly. But he does (or the writer of the scene does) involve Spock, and bring the issue of love into it, to leave no question. And the interesting parallels with Spock and Rayna suddenly make sense. It's obvious and heartbreaking the look in Spock's eyes, that he does know love, and McCoy is (unintentionally?) saying 'he is suffering [because of you]'. Spock knows. McCoy possibly knows (well, Bread and Circuses has a similar moment: "you wouldn't know what to do with a genuine, warm, decent feeling" "really doctor? :'(" "I know. I'm worried abut jim too".......). SO, Spock goes to him; not to immediately assume that he's 'erasing' memories (can he even?), or even that Kirk's asleep (Kirk would be so exhausted, that sort of exhausted sadness where you just lie down on the floor and you're awake but catatonic - if you've been there..you'll know) - if you think about all this context, that and the act of meld itself...and the aftermath that you DON'T see...there's more to it. This is a moment where Kirk needs, and Spock gives him what he needs. Himself. How much, you don't know, but a meld is intimate; it's going to help. But..is Spock ready for this? This is a critical point in the character arcs, right near the end, before the mysterious breakup gap before we get Star Trek: The Emotion Picture. Kirk in TMP, depressed and not himself, questionable in his decisions and motives, again. Common denominator? What's missing? Who comes back and improves Kirk tenfold? It's kind of nice that its handed to the viewer to fill the gaps - so much of the story seems to be in what's not said, or shown, but how the characters act and react; the breadcrumbs are there. TMP is a whole other analysis but the tension really ramps up. Kirk thought Rayna was his balm, but Spock is really what he wants/needs; it's always Spock. Kirk is a brilliant but flawed character; is it a flaw that he is so bound to another, as he describes in TSFS, their souls to be the one and the same? Who knows, but it IS what he is.
Another tidbit: Kirk, with great intensity, says 'I need him' of Spock in TMP. Recall The City on the Edge of Forever? The 'let me help' ≥ 'I love you'? And in the VERY NEXT EPISODE, Spock saying to Kirk, 'let me help', and Kirk replying, with feeling 'I need you'? Even when he doesn't say it, he does
