After Zhao Hai sent Muyu off, the only reason he had a drink with Muyu was because he didn't want anything to happen between them.
Zhao Hai knew that even though he was very popular in the hundred treasures world, he was still not as popular as Muyu. Muyu was the only legitimate successor of the cleansing sect, and everyone in the cleansing sect would fully support Muyu, followed by Zhao Hai.
This time, Zhao Hai did not want Muyu to have any conflicts with him because of the matter of old man heart prison becoming his master. Hence, he found Muyu to have a drink with him. He even told Muyu about the attack on him and mu Tianbo. He believed that Muyu would not tell anyone about this.