the thing about Spock is, like, whenever he comes in for a checkup or whatever, McCoy’s all like “god these readings are so fucked but that’s normal for you so… carry on i guess”
but unless I’m wrong about this (and I could be, i’m not That Deep into the lore yet) Spock is one of the first (if not the first) documented Vulcan-Human hybrid to survive into adulthood? so there actually isn’t an established normal for him. like you can take all the readings you want when he’s at rest and seems to be in good health and extrapolate from those, you can make predictions based on the norms of Vulcan anatomy and human anatomy, but there’s so much range between the two and so little precedent that there are bound to be unknowns
spock has two sets of eyelids and no one else knew about this until he temporarily went blind. if an entire second set of eyelids could come as a surprise just imagine what else is going on under the surface. there are so many question marks here.
i feel like this is what McCoy thinks about at 3am
Spock, the first officer whose advice was always effectual, possessed a strength of understanding, and coolness of judgement, which qualified him to be the counselor of the ship’s captain, and enabled him frequently to counteract, to the advantage of them all, that eagerness of mind in Captain Kirk which must generally have lead to imprudence. Spock had an excellent heart, positioned somewhere near his kidneys; his feelings were strong, but he knew how to govern them: it was a knowledge which his captain had yet to learn, and which one of his fellow crew members had resolved never to learn.
Dr. Leonard McCoy’s abilities were, in many respects, equal to Spock’s. He was sensible and clever; but eager in every thing; his sorrows, his joys, could have no moderation. He was generous, amiably cynical, interesting: he was everything but logical.
The Apple - In other words, the episode where Jim ruins a civilization while having a mild panic attack, Spock gets injured multiple times (but don’t worry, he’s fine because obviously he is half Vulcan, Jim), Bones disapproves of everything, and to top it all off, Jim fails to give the villagers “the talk”.