Steve turned around and smiled at the blond slut that ran towards him. Anyone watching would think that that smile was intended for Jenna - that he was smiling because he knew he had a chance to get lucky with her ... again. But that smile was actually for Jon, who he knew was trapped inside the body of that hot hot girl.
When Jenna caught up with him, Steve grabbed her arm and pulled her into a nearby janitor's closet. And the moment they were alone, Jon had control over his (uh, her) body. That was one of the conditions Steve made when he wished that Jon would turn into Jenna. He could only be in control of his own actions if he was alone or alone with Steve.
