The sound of ocean waves rushing back and forth – back and forth, back and forth – against the sides of their dingy ship, is the only thing he hears for a week. When they sit under the blazing hot sun, close to drowning themselves in seawater for some moment of cool – ocean waves, back and forth. When they sit with so little protection from the pelting rain, that they might as well be in the ocean – ocean waves, back and forth.
Those ocean waves are what lull him to sleep. They're what keep him up at night. They're what keep him company. They're what get on every one of his nerves. They're reminders of what idiotic decision he made in the face of marine capture and death, of freedom and a longer life.
He sits with his swords in the crook of his arm, legs crossed, eyes squinting and staring out at the vast, blue abyss around them. They're lost and they have no idea where they're going. This describes them in more ways than one, but he decides not to dwell on it for longer than five seconds with his food deprived brain and body.
His staring and squinting comes to an end as he turns his head to the man – no, boy – before him. The boy leans back as though their being lost is all a part of his big Pirate King-becoming plan. There's a look in his face that that tells him that everything's fine and dandy… and then there's a look in his eyes that tells him otherwise. In those wide brown eyes, there's uneasiness, questioning, and fear.
"We'll get through this, don't worry."
He cracks a smile as big as the moon.
"I have nothing to worry about with you here, Zoro!"