哨兵

哨 = 口 + 肖 : The little prince (肖) took a part time job working as a sentry (哨) for Sherlock Holmes (sh). In the aortas's bathroom (ao4) he whistles (哨), thereby giving the secret signal to Sherlock. Sherlock answers by holding up a mandarin (口), which is the secret signal of acknowledgement.

兵 = 丘 + 八 : Brunhilde and the soldier visit a burial mound in front of the engine. It is round like a ball like the deceased inside. To commemorate the round fallen soldier they put up a big eight-ball.