Just because she'd verbally agreed, didn't mean Genna had truly understood his words. She had a wild streak in her, the wolf's blood, as they called it. "Next time Lord Tyrell wishes for your company, you will send for me and I will join you in your walk. Do not venture forth with him alone again." He did not want to put one of his men on Genna to escort her around, but if he felt she was in danger he'd do what needed to be done.
And then she shocked him again. "Child, what makes you think your mother needs to see the maester?"