Seeking Solace
Hitting the cold water is a shock to Zoro's system, severe enough to leave him paralyzed for several seconds, his mind blank of all reasonable thought except for the fact that it is cold. So cold that it hurts, his exposed skin burning in the ocean's icy hellfire. For a moment he is frozen, slowly sinking, drifting in the absurdly quiet dimness of the sea's clutches of oblivion, before his thoughts return in a firework burst of neural activity, fragments and recollections of the last few minutes flashing in his mind at light speed.
Zoro forces his muscles to respond to his commands, though the water makes his movements sluggish and the temperature makes them clumsy. Against his body's wishes, he swims deeper, following the quickly sinking form below him. He refuses to lose sight of Law, whom he knows doesn't have much time in water of this temperature. Even a regular person would be in considerable danger after being submerged in this water for just a few seconds; a Devil Fruit user is in twice as much peril.
The noises of the battle raging above the surface are slowly fading, getting more difficult to discern the further Zoro descends, like a dream fading fading from the edges of newfound consciousness. Except it's backwards this time; he is going into the dream, not out of it. Memories stark and vivid in his mind only minutes before are quickly becoming murky and blurred in his mind's eye, a side effect of the water's numbing temperature.
He can remember the fight, with marines swarming Sunny's deck with rifles and cutlasses in hand. Not that they would do much good. This particular attacking ship's strategy was to overwhelm them with sheer numbers, and while it wasn't the greatest strategy, it was more effective than any of them would care to admit. Sunny's deck was only so large, and nearly every square inch of the grassy deck was packed with marines in a very short window of time, leaving little room for the Strawhats to maneuver without fear of either messing up or unintentionally attacking one of their nakama. And that was how Law had fallen overboard, attempting to dodge too late underneath one of Luffy's long-range Gum-Gum attacks.
Zoro remembers feeling the drop in the pit of his stomach surprisingly clearly, and the sequence of events following feels burned into his memory. The look of sheer surprise on Law's face was enough to send Zoro running to the edge of the ship, hastily sheathing his bloodied swords and diving overboard after him, not even bothering to remove his clothes or shoes beforehand. There was no time for that, and seeing the flicker of panic in Law's eyes told Zoro that he needed to hurry.
So he does.
Zoro swims deeper and deeper, ignoring the increasing pressure in his ears as the water pressure weighs down on his body, focusing solely on retrieving his nakama. Yes, he would go so far as to call Law his nakama. More than that, really. The affection he felt for the captain of the Heart Pirates went beyond the bond of allies or even nakama, and if there was one thing he knew for sure, it was that he could not let this happen. Not on his watch.
With a last heave of effort, Zoro kicks down a little farther and manages to snag the sleeve of Law's coat, pulling the doctor's limp body close to his own and holding him close. For a moment Zoro is too exhausted to move, even though his lungs are aching with want of air and his head feels as though it is being crushed by the weight of the water pressing down on them both. He pulls back for a moment to look at Law, whose normally tan skin seems ghostly pale in the light of the water, his lips slightly parted and tinged blue with cold. His storm-grey eyes are half-open and staring unfocused into nothing, which sends a thrill of fear racing through Zoro's veins, along with a renewed burst of adrenaline, which allows him to finally regain his senses and kick as hard as he can to try and get them both to the surface.
By now Zoro's chest is burning, and he fights the urge to breathe, knowing that he will only get a mouthful of water. Black spots flash in and out of his vision, mixing strangely with the almost ethereal feathery light rippling from above, where it seems the surface is just out of reach. With one arm around Law's waist to keep him close, Zoro flails with his other arm in the water, hoping it will help him to swim faster. Come on, come on..! he silently pleads, the surface and tantalizingly precious air seeming just a bit farther away as he reaches up with his free arm, desperately hoping to break the surface and reassure himself that he is close. Dammit...
Zoro is running out of time and oxygen, and his struggles are growing weaker with every passing second, his body feeling numb and exhausted. He feels himself start to sink slowly, as if falling in slow motion, but he is too exhausted to care as much as he should, with Law's added weight causing them to sink faster. Despite this he refuses to let go of Law, his characteristic stubbornness and pride not allowing him to give up on what he had set out to do.
The water doesn't feel as cold now, Zoro finds himself thinking absurdly, and his vision is darkening ever so slowly, a black haze descending over his vision. The burning in his chest is dull now, more like a background ache rather than an immediate concern, as it had been only moments before. But those moments seem like hours now, and Zoro can hardly tell if he's been falling here in this cold, numb oblivion for minutes or days, seconds or eons.
He knows that there is no one to save them. The battle is still raging above on Sunny's deck, flashes of color and movement just visible through the rippling water that is slowly but surely swallowing him up in its impossibly wide maw. No one will even notice that they are missing until the fight is over, and by then... It'll be too late.
Zoro realizes with a sudden pang of sadness that this will be the last time he sees his nakama for a long while. For a fleeting moment the thought makes him so distraught that he wants to swim again, to fight his way back to the surface and see them again. Luffy's joyous laughter, Usopp's outrageous tales and Chopper's childlike wonder and excitement.. Even Sanji's only halfway-insulting jibe of 'marimo' in his general direction, said with a teasing smirk. He'll miss all of them, but the spark is gone as fleetingly as it had come. The icy water has stolen the last of his strength, and Zoro can do no more than twitch his leg in a feeble last attempt to save himself and Law.
Law... Zoro thinks of him with another pang of sadness, that he will never know just how much Zoro loved him. Zoro had wanted so badly to tell him that he still wanted to be together even after two years of being apart, that he hadn't forgotten what they'd done together on Sabaody. That he had been longing, yearning with more of himself than he'd ever felt before for more of that touch, wishing that Law's gentle hands had been the ones to tend his wounds and Law's soft voice the one to comfort him when he woke up shaking and sobbing in the middle of the night from the same awful nightmare, reliving the day that he thought all of his nakama were dead. Zoro closes his eyes as he feels them start to sting with tears invisible in the water to all but himself. I'm so sorry...
Zoro feels a deep, sleepy numbness start to come over him, going deeper than the previous numbing sensation he'd experienced, which had been only skin-deep. This cold, this icy paralysis chills him to the bone. It is like tendrils of ice are slowly creeping over his already frozen skin and digging their way in with needle-like heads, permeating muscle and bone and blood with a chill so cold it burns. All over his body this pins-and-needles sensation is like fire, burning him alive with the intensity of the agonizing cold. Zoro feels as though he might cry out, though he knows no one will hear him.
But soon the burning pins and needles fade into a blank, all-encompassing numbness, and he doesn't even feel the cold anymore. The noises of the battle above are silent now, and Zoro briefly wonders if this means that it has stopped or if he is simply too far gone to hear it anymore. He is tired now, so tired... He can feel his eyelids getting heavy, and the darkening haze settling over his vision is becoming harder and harder to ignore.
He knows it is time when his lips part almost unconsciously, and icy water invades his lungs with its freezing touch, numbing him from the inside out and choking out the last of the fire that is his will to fight, like a lone candle flickering out as it succumbs to the pressure of the insurmountable darkness.
Zoro is fading fast now, and he surprises himself when his body obeys his commands, perhaps as a last testament of its loyalty and strength to endure with his mind. He wraps his numb arms around Law, whose eyes are closed now, holding him close and closing his own eyes as they begin the descent into nothingness, swallowed up by the sea together, seeking solace in each other's arms at the end of oblivion.