Under the [system], men had limited stamina. Each kill would deplete their current stamina. Having killed a few zombies, their stamina had dropped a lot. If these prisoners had continued to battle, all these prisoners would be wiped out.
After the apocalypse, each men were also valuable resources. Men are not solitary creatures. No matter how powerful a man was, there was a limit to how much he could do alone. Men could only survive this apocalypse if they worked together. These prisoners are all men with able bodies. Although they had committed crimes against humanity by engaging in torture, rape, murder or cannibalism, Yue Zhong had no intent to waste their lives.