Shark was the first person Battler met in Aather, and the one to give him a name, so there was definitely a good first impression! He's pretty much Battler's best friend, at least outside of Emerald, and the only one he's really opened up to. Well, that's not saying much, since he only described the barest details, but just the fact that he talked about the room at all is an indication of how much he trusts Shark. And the trust is not only because hurrdurr stupidly trusting; Shark has this great combination of caring and not being too serious that really puts Battler at ease.

Reverse?