"I'm aware of that, Old Pei, but as officers we have to obey orders."
Commissar Pei's division gets an order to fight the enemy that will surely doom them, and probably kill most of the men. As he tries to argue, this is the answer, and it summarizes the notion of the war in which lives of men aren't valued, and the communistic doctrine in which death is better than bringing shame to the community. Lower ranked officers have to blindly and brainlessly obey orders of higher-ups because disobedience is worse than death.
"Most of them were smart men who would have gone far in their lives had they had the opportunity and the education."
Yu Yuan decides to teach some English to the remainder of the division and is stunned by how quickly these uneducated men learn and are eager to sponge in the knowledge. It shows that every man has potential if given an opportunity, but unfortunate truth is that most don't get it, and are doomed to be just a number in war.
"In fact he too had been a mere pawn, not much different from any of us. He too was war trash."
After everything ended Yu Yuan realized the truth about his leader, Commissar Pei, who didn't end up much better off than his soldiers. He realized that he was just a man who was in position to create his own game within a game, but it doesn't change the fact that he was only a pawn, just like the rest of them.
