Katniss doesn't know who this girl is - but she knows that she's not supposed to be there, so she follows after her. She's running, trying not to trip over bushes and trees and whatever else might be there.

Until they come to a clearing, and Katniss slowed to a stop, her expression creasing into a frown, "... This keeps happening ... why does this keep happening? You're not supposed to be here either."