Shepard watches him use the ability with an abrupt sharpness all at odds with the way she's relaxed in the last few minutes. It isn't the tension in her posture that's changed, or any movement of the head, or hands— it's the eyes. She is too used to being watched and judged for danger at a distance to react, but...

The water fizzles out, and Shepard lifts her chin ever so slightly in acknowledgement. Most of being dangerous was just about being willing to hurt people, and you couldn't be a Victor without crossing that line; Finnick had never been helpless, in her mind. Now, she knew he could be more than that: a threat.

Unless what he was saying was true, one for all and all for one and all. Another thing Shepard couldn't quite trust.

"I'm a biotic. They're— I can manipulate gravity. Part of why I joined up with the Alliance in the first place, before all this," She offers a quavering, sweeping little circle of her hands. All of this, Caldera and Panem, and everything else, "They had some way of suppressing it, in the Capitol. Sometimes they'd turn it off in Arenas, which was a real bitch. I need twice the calories just to stay alive, when I've been using my biotics."

Which really put the "hunger" in Hunger Games, for her, as he might imagine.

"It's been a long time since I've been...Me. You're telling me I can get that back? Just like that?"