In his tell-all, ex-Navy SEAL Matt Bissonnette says he and fellow soldiers slept just before taking out Osama bin Laden. One of our commenters says he also caught some shut-eye while shuttling between missions. Harry Rubenstein writes

I served in the IDF in the Armored Corp. I had absolutely no problem falling asleep anywhere and anytime. Even standing up in my tank. One hand on a handle, the other gripping the mortar and my helmet lodged snugly on the inside of the tank. Falling asleep during transport was quite common. 

When at war, soldiers take sleep when they can get it.