Doing good without hoping for rewards wasn't the least bit in line with Ling Han's personality. Since they wanted him to open up the Light of God, then how could he not take advantage of this chance to get some benefits of his own?
Putting it in a different way... asking an ultimate warrior of Heaven Tier to do something for them while offering this little bit of payment, it was already nice of him to agree.
"Let's go. We can't have them wait too long. It would be impolite," he said.
The two girls instantly rolled their eyes at him. The truth of the matter was that he had spent the whole day and night concocting alchemical medicines rather than doing any kind of preparations. He was obviously the one to have them wait pointlessly for a whole day, and he actually dared to say that. He really was shameless.