I. INTRODUCTION On an ordinary day in May 2017, Yang went downstairs to take the express, and when he entered the elevator, an old man was smoking. For his professional instinct, Yang advised this old man not to smoke in the elevator, but the old man therefore argued with Yang. After arguing in the elevator, they went to the property management department located on the first floor to find property management staff. At that time the staff appeased and persuaded the old man, Yang left to take his express. About 15 minutes later, Yang took the express and came back. Someone told him that the old man that just argued with him in the elevator was unconscious due to a heart attack. Before the arrival of the 120 ambulance, Yang, as a doctor, gave the old man a first aid measure including cardiopulmonary resuscitation, but Yang was unable to save the old man ultimately. The close relatives of the old man thus sued Yang and claimed a compensation of more than 400,000 yuan.