Dramatic Irony: Realizing the Neo-Atlanteans are here on the island, Sanson wonders why the hell the Nautilus isn't doing anything about it. We then find out the command crew only just found out themselves (and by a chance detection of the Garfish's magnetic signature).
Fire-Forged Friends: Sanson rescuing Marie. The two characters haven't really had much interaction in the preceding episodes, but their (mis)adventure here ends up forming a bond. Sanson becomes very fond of and very protective of Marie from this point forward.
Insane Troll Logic: Nadia's Vegetarianism argument with Jean veers into this.
Nice Job Breaking It, Hero: Downplayed, but Nadia is arguably the reason — or at least one reason — the Nautilus crew didn't realize there was a Garfish docked on the other side of the island until it was nearly too late. Something set off Nadia's Blue Water the night before, implying there was danger somewhere on the island. But Nadia not only had run off from the others after her blow-up, but immediately got into a fight with Jean the next morning instead of telling him (or sharing the alarm with the command crew).
