Johanna was still getting used to the island. She'd adjusted to it on the surface -- pitching in, doing what she could -- but there were parts of it that she wasn't so sure she was used to yet. The people for one thing -- people were much more friendly than back home, much less guarded. Yes, people had their secrets, but they were overall less afraid than people from Panem.
And the ability to do what she wanted, when she wanted. She'd been so confined for so long, that having freedom was actually pretty heady a thing. Even after helping to rebuild her District for a while, she still wasn't used to freedom. Yes, of course she was here to help rebuild, but there was still more freedom than she'd ever had.
Right now, her freedom consisted of just sort of wandering aimlessly along the beach. Or wandering aimlessly until she came upon someone. "Hey," she called, stopping when she was a couple feet away. "Didn't realize anyone else was here right now. Sorry, didn't meant to interrupt your thinky times."