Instead of killing them, Sun Tzu could have simply replaced them with two more. It wouldn't have caused any harm and the job would still have been done with the replacements. Sun Tzu could have respected the king's wishes and not had him beheaded. A second option would have been to replace Sun Tzu and appoint someone else to lead the army who could have better controlled the army. Regardless of what happened, there were deaths, which flies in the face of the whole thing. Another theme of Art of War concerns orthodox and unorthodox approaches. One could see that having no one die would be an orthodox approach, but instead Sun Tzu opted for an unorthodox approach and killed two concubines. It would have made sense for Sun Tzu to move on with two more people, but on the other hand, two deaths are nothing compared to the amount it could have been. They were lucky there were only two deaths and not many more. Even if the alternatives seem plausible, the job would not have been done as well and Sun Tzu would not have become general and successful. If they simply replaced the first two concubines, the others would not change their behavior and would simply accept being replaced until there were two who would listen. The fact that they saw Sun Tzu kill the concubines was necessary for the others to realize that he would not tolerate any disorder..