Aha, so this guy takes promises very seriously. Good to know. But he's also apparently more selfless than he might seem. Senku has no hard feelings at all about the kidnapping thing. Waking up on a weird island in another world is a wild ass thing to have happen to you.

"You don't even know her, right? And you still did everything you could."

He's impressed! Not that he's really any different. Senku doesn't openly express emotional attachment to people most of the time, but he's always wanted to save everyone — whether that's at home or here. The end goal is more or less the same.

"Good thing we didn't capsize, though, with that freaky shark thing in the water."

He laughs because of course he does. He just does that.

"Waiting til morning wasn't too bad, huh? Imagine having done that in the dark."