Although he was thoroughly enjoying the show Jessie and Red were putting on, the presence of this new girl caused Sean to rethink his plans for the little women.
He had allowed himself to get too attached to Jessie, learning too many details of her past life. This made him think of her as a Friend who he would eventually like to be able to return to her old life.
Looking at Red and the state she was in when he received this latest 'present' from Grand-dad, Sean realized too much had occurred for her ever to be returned to the real world. He couldn't allow himself to identify with her humanity if he was to keep her, and Grand-dad had obviously done too much to her for him to let her free without risking unthinkable consequences for him and his grandfather.
Sean resolved to deliberately keep his knowledge of Red's life to a minimum. He didn't want to know her real name or any detail of her past. To him she would be known only as Red.
Sean also realized that the only way he could assure that if he were ever to release Jessie, she would have to have as much at stake as himself in assuring that Red's fate is never discovered.
Sean said to Jessie, "I see you are enjoying playing with Red, how would you like to have her as your personal sex slave? You can do what ever you want with her as long as you let me watch."
At first Jessie was repulsed by the notion, and yet she found that part of her was aroused by the idea.