The blood of those afflicted by the plague is not something one can casually drink; once consumed, one would also contract the plague.
Gong Juechen's action clearly showed his intention to contract the plague himself.
Everyone thought that Doctor Gong had gone mad.
An Jing and Xiao Changyi rushed to the Medicinal Diet Hall from the temporary palace as soon as they learned that Gong Juechen had drunk the blood of someone with the plague and questioned him about why he did so.
However, Gong Juechen appeared unconcerned, rummaging through the medicine cabinet and, with a teasing smile, said, "I'm not crazy, I just want to test the medicine on myself. It's inconvenient to constantly have others test it. It's quicker and more convenient for me to do it myself."
Listening, An Jing and Xiao Changyi felt uncomfortable but said nothing, both just watching Gong Juechen with complex expressions in their eyes.