During the tearing of the contract, Berowne mouths Longaville's lines along with him.
While the movie's concentrating on what is obviously WW2, one of the paper shown announces the end of the war on November 11, which is in fact the date of the end of WW1 in 1918 (the end of WW2 being on May 8, 1945 in Europe and August 15 in Asia).