"It had killed," Lan Zhan said, and the words were ashen in his mouth. "It would do so again, in time. The Burial Mounds would not stop it from killing again - merely direct it's attention to a penned in population."

If it had come in, someone would still have to kill it -- and it would have been Wei Wuxian. It was still sick. Being in the Burial Mounds would not have changed that.