He grabs her head and starts to fuck her mouth hard making her gag even more, she feels his balls tighten, she knows what’s coming next.
As Mark heads up the stairs the girls are at the door trying to get Anna to open it to find out what happened, they see Mark approaching the part to let him through he knock and says its Mark let me in now! She opens the door a crack and he goes in, closes it and locks it behind him.