When Liza is shown the house the government is giving her, she hears termites in the walls. However, she's plainly seen wearing the special earrings that suppress her "super" hearing.
When the police shoot the boy in the school and are right next to Liza, she doesn't react to the loud nearby gunfire even though she has "super" hearing. Ironically, it was a gun fired near to her ears that first damaged her hearing, thus causing her to try the experimental drug that gave her "super" hearing.