Counterpoint
When he reaches Sound, he finds he hates how quiet it is. It's boring and silent, dreary and oppressed, and he hates it for being such a poor distraction to the noise that's been thrumming in his head since the Valley of the End. Since before the Valley, and as much as Konoha had been driving him crazy in not making him stronger fast enough, it had - at the very least - provided a very welcome background noise that had drowned out this other sound in stretches long enough to keep him sane. He wonders at that irony for all of two seconds before shoving it away. (Sasuke very much doesn't want to come to this thoughts only logical conclusion, that sanity would have made him far stronger than any Jutsu that could ever be taught. He finds the self-delusion comes easier with every repetition.)
But with no respite in the silence of Otokagure, he is given far to much time and space (the very things he had craved from Konoha) and there are stretches where that infernal noise was the only thing to occupy him. It is regular and steady, like a drum echoing in his own heartbeat, but off, and hums in the space between one pulse and the next. The beat is identical to his, might as well be his, but it's not his and whatever it was irritated the shit out of him in a way only one other thing (person) has ever managed. This small realization brought it's own little epiphany - which is brutally buried in the darkest corner of his soul half way through completion, the same place where every thought pertaining to that person goes.
Yet even with his ability to ignore any dwelling thoughts, it does not mean he can ignore the sound itself. While it always fit neatly in the space between his own heartbeats, it also seemed to carry a tempo of its own, unaffected by whatever he could do. This went as unimportant until he noticed that - when his heart quickened and became agitated in sparing or fights, it was this off-beat rhythm that he would subconsciously use to regain his calm. When this happened, he became utterly unstoppable, and nothing short of the Snake Sannin himself could halt his flow. Even that was becoming less and less likely - the rate of his growth astonished everyone who knew, and frightened most of them on top if it.
He knew where this calm came from, he just didn't want to admit it.
It isn't until Kidomaru brings it up in a spar that it really gets to him. As it was, it puts him in such a foul mood that he critically wounds his sparing partner, terrorizes every servant to come within sight, throughly antagonizes Kabuto who comes later to tell him off, and is such a brat that even Orochimaru gets fed up and sends him on a mission just to get rid of him for a few hours. He is vaguely proud of this, until the sound returns and his mood darkens again.
So when after three years of separation the source of the sound itself is once again presented, Sasuke is surprised to find that all the thoughts of Naruto he buried in the darkness have not been idle after all. The infernal calm settles almost unwillingly over him, and he feels them stir in his shadows. They've been growing, like he's been growing, like Naruto's obviously been growing, some sort of tree that has set roots down in his heart and sheltering branches over every part of him not tainted with vengeance or hate. Some part of him seethes over this, that this idiot is for once protecting him like he always boasted he could. But the calm is still working, and if Sasuke's vision is tinted red,it is only in the space between them; masses of yards and miles and lifetimes of tangled string that is this bond he thought (hoped) he had severed.
(It had not broken, mearly grown longer and stronger to compensate for the distance. It was also a mess, reflecting their relationship; but was bright and clearly defined even through the knots and snags, just like their memory.)
Because after all, he and Naruto have never been the same. If they shared backgrounds and outlooks and heartbeats, how would they keep each other grounded? Naruto is his equal, his balance, his counterpoint, and if one were to tip to far, the other would be able to even the equation. Sasuke trust's in this, because there's nothing else to really trust about each other - they were both totally unpredictable like that. So Sasuke keeps their calm (he was always the one to be level-headed) while telling him it was a fluke and how he will kill him, and Naruto loudly calls him a liar and exactly how hard he's going to hit him and drag him home, and just like that - nothing had ever happened between them. And just for a fleeting second, Sasuke can't help but bask in the prescience of Naruto, because every tree will eventually seek out the sun - and he knows if he survives Itachi, it will be no different for him.