How does Maria treat her students in the play, Master Class?

Maria is an intimidating presence for the young students who have come to learn from her. She can be domineering and contemptuous, with an acerbic, mocking sense of humor. She is impatient with interruptions, browbeating the stagehand and using the accompanist as the butt of her humor. She is also ruthless in her appraisal of her students' efforts.