"No, you aren't keeping me," Severus answered with a shake of his head.
Though he frowned ever so slightly when she mentioned heading back. Presumably to the hotel. That was, of course, his destination as well, but he knew better than to offer to accompany her. After all, that might have been her polite way of taking her leave, and besides, if she was a policewoman, she hardly needed an escort. He felt certain that she could take care of herself.
"I was just going that way, myself," he added, with a slight shrug. That way, if she wanted company, she could propose the idea, and if not, they could go their separate ways. And he could always find some excuse to dawdle, so she wouldn't think he was following her or anything that could appear threatening, like that.