Shrugging uncertainly, B says, "It could've been. Busting me out of prison without killing anyone. Or throwing himself in front of a pirate weapon for me. Or deciding to make a plan and stick to it, for the boat. All of them might fit the bill."

Graduation is so sticky. He's... maybe worked out what it was that did it for him, after much thought, years later, but it seems like such a dumb thing to graduate from that he's never actually told anyone.