Pandora could see a momentary look of alarm in the young man's face, and immediately she recognized that somehow, this boy knew. Perhaps she would do more than simply play with this one - he needed to learn to keep his nose to himself. The hand on the woman's arm showed care, obviously a woman who was dear to him.
Therefore, a weakness.
She pulled out her wand and cast an Imperius on the woman, commanding her to slip between two buildings into a side- alley.