[Which one?] Lucien's question leaves Nea and Saria very confused. They want to think he's referring to which one will use the teleport gems first, but that would mean he doesn't know how such treasures work, and it seems pretty unlikely.
Also, his teasing smile makes it clear that he has 'less noble' intentions with them, so while Saria blushes just by wondering what that is about, Nea gets upset.
"You devil, what's on your perverted mind?!?" Nea asks in a tone more concerned than angry.
"Isn't it evident?" Lust asks.
The cute mother-daughter Mermaid pair still seem a little confused or are just avoiding accepting that, so Sloth starts talking in her usual sloth tone. "We only have two instant teleport gems, meaning only two of us should be able to get out of here that way..."