One of Mr. Sun's mentors, with respect to both his medical and political education, was Ho Kai, the foreman of the Hospital and the College. A de-facto erudite Chinese elite, Ho Kai was a physician, a barrister, a merchant, and the first Chinese member of the Legislative Council. He lectured in the College of Medicine on forensic medicine and physiology, and had always held that China should modernize herself through westernization. Another mentor of Mr. Sun was James Cantlie, the Dean of the College and a surgical professor. While Mr. Sun learnt medicine from Cantlie at the College, the two of them would soon be very close, both in the practicing of medicine and political activities. It was through Cantlie that Mr. Sun escaped from the illegal imprisonment of the Chinese Legation at London in 1896.

In 1887 Mr. Sun, then at the Canton Pok Tsai Hospital, heard the news. Immediately he applied for the College of Medicine, considering that the courses were in compliance with that of British medical schools and that a qualification fulfilled in Hong Kong was better recognized internationally. He longed, of course, to get in touch with the diverse cultures of Hong Kong. Soon he left Guangzhou for Hong Kong and became one of the 12 students of the College of Medicine in its first year. He graduated after completing a five-year curriculum.

In 1892, Mr. Sun graduated with distinguished results and was able to acquire the license for practicing medicine. As the first-generation graduate of the College of Medicine, he was awarded the diploma by Governor Williamson in person on the graduation ceremony held at the City Hall. Five years of medical study had made him a licentiate, while his encounter with men of critical political views in that period made him a fighter for reform.