At the realization that they somehow actually heard that, Ariel's eyes go wide and she covers her mouth with her hands in spite of the fact that she hasn't actually said anything and couldn't if she wanted to. Which, as it turns out, she really wants to.

Slumping a little, her eyes move slowly from one person to another, unsure if she ought to tell the truth or silently laugh it off. They all look as startled to hear it as she is to have been overheard.

Rather than giving a committed answer, Ariel gives a little shrug, looking uncomfortable.

You can't even keep your big mouth shut when you don't have a voice, what's wrong with you? she thinks miserably, her brow creasing. It hasn't actually occurred to her that if they heard one thought, they could hear the rest. Megan said it, but that doesn't mean it's actually sunken in as reality.