what tense situation occurs at the county jail? How does scout help her father in this scene?

A mob gathers at the jail, intending to take Tom Robinson and lynch him. Atticus confronts the men, and Scout intervenes after recognizing Mr. Cunningham. Scout innocently serves to remind Mr. Cunningham about the way her has helped his family..... as well as the fact that his son is her friends. As a result, Mr. Cunningham tells the mob to leave.