"I'm with you on this," Leo addresses Carlisle, his hands shoved into his pockets. He looks unhappy being this close to the water as it is, and if one of them is especially perceptive, they might be able to catch the fact that Leo actually looks a little scared as he looks out at the waves. He doesn't seem at all ruffled by the appearance of Glacius. He's seen stranger. Heck, he is stranger in his true form.

"Looks like if you fell in, you'd just go straight on down to the bottom like a rock." Or maybe that's just him. He's a monster mostly made of fire and smoke under the human guise, so it stands to reason he wouldn't like the opposite element very much. Leo's also extremely dense in his human form, so he's really talking about himself with the gloomy predictions he's making.