Trunks surprises him, but only for a second; he was far from being quiet, and his hand comes back down, both slung into his pockets.

"This place was holding him back, y'know?" There's some jest, but not entirely untrue: the guy liked a fight. But there's a beat, before Tidus asks, "...You got any idea? What he's going back to do?"

He knows they're from same...ish worlds, not the same. But Trunks might know anyway. Might've been more curious than Tidus to ask.