How do Felix, Zelda, and Chaya escape from the boxcar that is carrying them to the concentration camp in the novel, Once?

When the prisoners discover that a part of the wall in the boxcar is rotten, they are able to kick a hole in the wall big enough from a man to escape from the train. Some of the men who jump are killed by Nazi soldiers, but others get away. Felix, Zelda, and Chaya choose to jump from the train. Barney, however, stays in the boxcar with the other children who are too afraid to jump.