Let me just point something out here. It doesn't matter, in any way, what the girls response is to his texts. He is wrong.
I don't care if she was spouting sexual content left and right. He was wrong.
It is wrong for a married man to carry on a text relationship with a girl young enough to be his daughter. It is wrong for him to tell her how beautiful she is on a constant basis. It is wrong for him to try to "meet up" with her at the door to the dorms. It would not be allowed of a male student who was single, why in the world would it be appropriate for a married man?!
That being said, the girl gives responses that are not necessarily intended to continue the innuendo and banter. She is trying to be positive and keep it innocent, even though he is obviously fishing for more. If you are a student and this man has the power to make your life on campus a living hell, you will make sure to not step on his toes. She knew full well that this man is the big cheese.
Obviously, those of you who think she was trying to start something have never been a woman trying to deal with a persistent man. You don't want to hurt his feelings, or in this case step on his toes, yet you don't want to encourage. That seemed to be the tone she was exerting there.