Back in the Desolate Human Valley, Yi Yun had seen Lin Xintong refine bones. He then tried to manipulate the Power of Desolates Lin Xintong had extracted from the desolate bones using the Purple Crystal and he had succeeded.
This was what started Yi Yun's ambition to become a Desolate Heaven Master. He had obtained Su Jie's notebook from Lin Xintong, which was his first step in becoming a Desolate Heaven Master.
In this Desolate Heaven technique tea session, when Shentu Nantian requested Yi Yun's cooperation, Yi Yun had planned to use the Purple Crystal to interfere with Shentu Nantian at the critical moment to screw him over.
Hence, even though Yi Yun knew Shentu Nantian was targeting him, he had played along and accepted the challenge.
Yi Yun was not a magnanimous person. He would return things in fashion to whoever went against him.
