"What do you mean they left?" the confusion on Gil's face was justified. Mostly because Midnight had mentioned that Walker and Su had left right before he got there. And by right before, he means minutes which was ridiculous.
To be fair, they had left using the elemental rune teleportation formation and Gil had arrived minutes after. It was just bad luck to be off by so little in timing.
While Gil, Zephyr, and Ventus were going to take a few moments to explain their experiences to Walker, they knew very well that they might not see him for a few days. If not weeks since Su had brought him to explore something new.
With their luck, they would discover some underground cave or some new species of monster in the water. It could be a while before all that was recorded or handled. Gil knew that this sort of twist was fairly tame for their party.