A/N: Heavily quoting from chapter 512. What did Zoro think to end up on Mihawk's island? This is my theory, please tell me yours.
"If you were going on a trip," Bartholomew Kuma loomed before him. "Where would you like to go?"
The world had erupted around them in a rush of panic and fear because for the first time Zoro could remember, Luffy ordered them to run. The enemy, the man who almost destroyed all of them once, is reaching for him again when it strikes Zoro strange; he faintly registers Chopper's deathly rattling from around him and Usopp's frantic gibbering from beside him but what Zoro really listens to is the emptiness in which Brook is down, only gods know how the rest of them are, and Luffy is silent. The swordsman can't hear the familiar shout of attacks followed by the whistle in the air as a rubber fist stretches out or snaps back. He can't hear their captain call their names despite two of them being collapsed before an enemy neither of them can win.
It comes to Zoro with a sort of frozen clarity that today, they won't just lose the battle. They will lose each other.
Stronger, Zoro thinks angrily, a promise and confession whittled down into that single word. The taste of blood in his mouth is desperate and bitter and as Bartholomew Kuma's hand draws closer, Zoro remembers a piercing gaze, a flash of black blade, and unshakable strength. Like-
(Usopp blinks at the empty space his friend used to be. "...Zoro?")