What is the importance of Elizabeth's twenty-four-year-old coworker in the novel, Want?

Elizabeth's twenty-four-year-old coworker at the charter school often shares a classroom with her. She resents his youth and inexperience, as well as his attachment to disciplinary enforcement. The twenty-four-year-old similarly dislikes Elizabeth, even reporting her at one time for being condescending to him. The more Elizabeth leaves school early, the more she worries the twenty-four-year-old will report her, and cost her her job.