Scout says she doesn't mind being a ham for the performance, but the costume is not comfortable. Scout lists the many discomforts of her costume saying, "it was hot, it was a close fit; if my nose itched I couldn’t scratch, and once inside I could not get out of it alone." We know Scout wants to be as independent as possible, so her needing help to take off the costume is a major problem for her. This also hints that there may be a situation in which Scout's costume becomes problematic because she can't get out of it along. This literary device is foreshadowing - it's showing that some trouble might befall Scout because she can't get out of the ham costume.
Suddenly disappear. That conveys the thought that something so dramatic happened to society that the first amendment is gone. That should stir every American into finding out what this sentence is about. The first amendment is the backbone of American Democracy and should not ever be ignored.