Lin Zheng had relaxed his guard because he had believed that the person before him was the real Xian Yun.
Realizing that Lin Zheng's level of vigilance had decreased, Xiao Tian took advantage of the situation to finish off the opponent, who had a cultivation twenty layers above his own.
After killing Lin Zheng and freeing the demon spirits, Xiao Tian ordered the demon spirits to enter the void so that Ah Meng wouldn't suspect him when they passed him at the mouth of the cave later.
When he was only halfway to the outer area of the cave, Xiao Tian met Ah Meng, who was walking into the cave.
"Why do I smell blood from your body, sir?" asked Ah Meng, frowning.
"Blood, what do you mean? Maybe that's just how you feel, didn't I tell you to keep watch outside? What are you doing here?" asked Xiao Tian while looking at Ah Meng.