How does Scout prevent Mr. Cunningham from becoming violent at the jail?

Scout talks to Mr. Cunningham about her friend and his son Walter. In the past, Scout has had to stick up for Walter, tryinng to make the teacher understand why he had no lunch, being told by Aunt Alexandra that she can't play with him because he's trash. Scout approached mr. Cunningham to tell him about Walter in order to change his perception about what was going on with the trial, and the things that were making the men outside of the jail become more hostile. And guess what; it worked, and he got all of the other men to leave with him!