It's been ages since i last touched that Teacher and student scenario with Rebecca and Jimmy which they make such a good couple together~
Jimmy's getting in a sticky situation after Rebecca found out there was a writing insulting about her breath. She requested the responsible to SEE HER at the principal's office for some lesson that he won't forget. Besides, he haven't attended to her personal kissing lessons so she had to recover the missed hours by extending the working day!
...The skulls and strong language in the radio is actually a recording of her screaming at Jimmy. Hence why people outside thinks Rebecca is yelling at him. The whole recording also helps to muffle the kissy noises happening inside the office.