Lily wasn't sure if she should be offended or flattered by Scorpius' reaction. The thought to be offended crossed her mind first, because she was sure he had thought her incapable of looking that nice. Flattery crossed her mind second, because no matter what he thought, he did obviously like what he saw at that moment. Since she generally liked what she saw when she looked at him, it was nice to have it reciprocated, even if it was a one time thing.
"Malfoy," she replied back, coolly as he greeted her. She watched him nod toward the door leading to the muggle side. She gave a slight, acknowledging nod before he walked towards the door. As he left, she remained still, not even following him with her eyes. She didn't want anyone to catch on to the point that she was actually going somewhere with him.
She gave him a few moments once he stood outside before turning and walking out the same door. She hoped it would look like she was giving him time to get away. Once she got out there, she saw him waiting for her. "I dohope my dress fits your high standards," she said sarcastically. She was in no way going to make this easy for him. She was afraid to. She was afraid that her real feelings would come out.