Ianto just took a moment to tread water there, breathing, trying to catch his breath and make his heart slow down a little. Luckily, they could both swim. Ianto wasn't sure that he could have handled trying to rescue the other from drowning in the state that he was. He could only just keep himself from drowning, let alone do much of anything else. After a moment, his brain calmed down beyond the 'oh my god what in god's name was that' that it had been stuck in for the last while, and instead he could think enough to be able to turn and speak to the other man.

"Are you alright?" he asked, treading a little closer to Sulu. "What... What the hell was..." He couldn't seem to get the rest of that sentence out of his mouth, however. So instead he settled for the next thing that came to his mind, which was unfortunately, "...we just jumped off a cliff..."