On Fire?

When he heard their words, only then did the fuming Master Third Sun realise that he had been so angered by their interruption that he had stormed out without putting down the whip. Under their suspicious and inquiring eyes, his heart stopped for a moment. 

He said calmly: "Haven't I already told you that I am refining pills? I was just about to take the blood of a spirit beast to add to my mixture when I was interrupted by you."

"We can understand taking blood from a spirit beast. But why do you need a whip for that?" One of them asked suspiciously. 

They too had used spirit blood as an ingredient in the past as some pills do indeed require spirit blood. However, isn't a knife used instead? Why was he using a whip? And a one that had been soaked in medicine liquid as well? What kind of pill was he refining? Why were the ingredients he used so strange?