The reason Chen Xuan did not kill or cripple the remaining military experts was because he knew he had thoroughly subdued them both physically and mentally. He could make use of these fellows for any errands down the road.
In the Sacred Martial Empire, the status of military experts was extremely useful, and Chen Xuan happened to need a vast amount of elixirs, divine pills, and secret techniques that could temper the physical body and raise his upper limits.
As for plundering the top-tier Laws within their bodies?
Chapter 3725