Dean reaches Shiala just in time for her to already have come back up to the surface, and Dean punches a tentacle out of the way as it draws nearer to them.

He wants to hear what Shiala has to say about how she's feeling, but that tentacle he punched comes back, angry, and swipes Dean. He goes under for a few seconds, but is able to come back up again, shaking water out of his eyes.

He doesn't realize he's been hit with the toxin yet, but he'll figure it out soon.