At age 22, Zayne obtains his MD and joins Linkon Central Hospital's Cardiac Surgery division as attending surgeon. The wiki notes him simultaneously as chief medical officer. Linkon Central Hospital and Akso Hospital refer to the same institution — a wiki-side naming inconsistency, not two different jobs. He is the youngest person in this role. His teacher at this stage is Dr. Noah, the former Chief Medical Officer of Akso Hospital and — crucially — MC's original cardiologist, an old acquaintance of MC's grandmother Josephine.