I would have to dissagree with you there. As unrealistic as it may seem, Kurono is not the same person as he was when he first entered Gantz. He cannot simply turn his back on his companions who fought and bled with him. For all he knew, he was the strongest gantzer there at the time. If he chooses to go free, then he forsake his responsibilities as team leader. I doubted that kurono picked 1 because it seemed like he was just repeating what everybody was encouraging him to do.

Also, why the heck revive nishi if he wanted to get out of there. He obviously wanted to know what the hell was going on.