In chapter 15, what stops the men from attacking atticus

A mob shows up at the jail to "take care" of Tom Robinson. Despite Atticus’s orders to stay home, Scout, Jem and Dill show up at the courthouse. Atticus refuses to let the mob near Tom. When things get heated, Scout makes her way into the crowd and asks Mr. Cunningham about his boy and his life. The simple and kind gesture of a little girl seems to remind Mr. Cunningham of the folly of his ways. Scout diffuses the hostility long enough for Mr. Cunningham, and the mob, to realize just what they are doing.