Hermione had to get him to leave before he was spotted. When she was confident in the fact that there was no one else waiting out in the shadows with him, she dried her wet hands on a towel. She turned around to announce that she was going to take advantage of the clear skies and take a walk before bed. Oliver's offer to join her was immediately quashed by his father's insistence that it was too late for him to be outside. Bedtime was fast approaching.