The Boy in the Striped Pajamas
By John Boyne
An event at the end of the book that relates to the conflict
Bruno climbs under the fence. They both go look for Shmuel's Dad & they get pushed into a gas chamber by a whole crowd & die.
it's important because they're good friends even if they're on different sides of the war. & because Bruno wants to help Shmule & they end up dying.