It doesn't look exactly like he's interrupted something; the girl is leaning over to inspect the gate hidden under a stairway, while the youth leans against a nearby wall almost as though he's standing guard. (Or at least, he was before their near-impact.) Ryoji gets a brief blank look, before the boy glances at his companion and then back. The reply is hesitant and a little uncertain. "...Hey. It's fine."
II