They cannot endure her fearful screaming. AND She voices aloud the terror they all feel inside.
Mrs. Schachter is in the cattle car with other Jewish people who have been rounded up by the Nazis. The people do not know where they are being taken. The way they've been treated so far by the soldiers indicates that it probably won't be a happy place. Mrs. Schachter's reactions to being crammed into the cattle car with many other people and being hauled off to likely a terrible place mirrors what the others are feeling. They are afraid for what is to come. Also, her screaming is so terrible and consistent that it scrapes at the people's minds. They cannot take her behaviors any more so they bind, gag, and beat her. Later, they find out Mrs. Schachter is right. They do get off the train at Auschwitz where people are being gassed in chambers and the bodies are burned in furnaces.
