Lu Shu did not ask for anyone's help. Instead, he took the lead and went with Chaos to kill. Lu Shu still had his own intentions, as he wanted to kill the culprit in private, and not be questioned by others.
Lu Shu did not expect Lu Xiaoyu's abilities to be exposed. Lu Shu was on his guard. There were some secrets Lu Xiaoyu and Lu Shu possessed that he did not want others to know about.
Now, the Heavenly Network dominated the situation. Thus, Lu Shu was generous in giving Nie Ting the refresher fruits.
In the past, he had hidden these fruits as he could not protect himself. But now, things were different. He was the Ninth Heavenly King. He did not have to worry about his safety, unless it was the Puppet Masters!
Of course, even then, Lu Shu did not want others to know that he had an infinite supply of refresher fruits.
Furthermore, Lu Shu did not want to reveal the secret that he could earn distress points from others. He had far too many secrets.