There's only two things about that which worries her. One, that the propelling force is Tidus and... no, that was pretty much it. Eight was used to seeing gravity-defying devices before, so the principle was sound, everything else...

Eight is going to take a step back, but mostly because she needed to be cautious around the water stream. If this goes badly, there really wouldn't be anything Eight could do to help him.

"Are you going to float over the barrier?" It's the only thing she could think to say.