There is right, and there is wrong.
Jayne's trying to wrap his head around the concept. It doesn't quite fit, so he's wrinkling his forehead, twisting his neck to see if it squeezes in.
He's always thought the 'verse ran on the principle Every man for himself (or herself, never let it be said that Jayne Cobb was prejudiced against the fairer sex.) In fact, it's how he's always run his life. For himself. Hell, he even took the job on Serenity because it was a better deal.
Jayne can pinpoint the second the sliver of doubt crept into his brain. A sharp crack of gunfire, the shadow flying by, the sound of a body slamming into the ground, dead weight.
Only thing that made that moment right was the fact that he was still alive. Only thing that made that moment wrong was the fact that he was still alive. And the kid wasn't. And he was still alive.
His forehead wrinkles some more. Right, wrong, it's getting all jumbled up, and giving him a headache.
A private bunk is a luxury that Jayne never expected.
Granted, on a ship this size, it's not much of a bunk. The lighting is gao-se, and you couldn't swing a cat. The cap's is a mite bigger, but that's to be expected. But it's his. It can locked, and he can be alone.
The others would be surprised, but he sometimes has an inner monologue going. (They'd be surprised at that word, too, but he heard it once, and decided he liked it, so he learned it.) It's a mercenary's life. Lonely, never settling down in one place, only your weapons to keep you company. Why is everyone shocked that they've got names?
Jayne's bunk is a tidy place. Sorta. Just like his brain, he knows exactly where the useful tools are. Everything else is relegated to clutter, to background noise. A good quality for a mercenary who's still alive, focus. Can't get distracted by trivialities.
There are other parts of the ship that he likes well enough, galley is good, with all that food, and a table big enough to clean weapons on, but, given a choice, there's always his bunk.