Shi helps a colleague disinfect after returning to base.[Photo/Xinhua]

The next step was taking a warm shower in the semi-contaminated zone. Shi had to take showers every time he returned from a transfer mission.

"I once transferred six patients in a single day. That meant six showers. My skin became somewhat chapped," he says.

For Shi and his colleagues, eating at irregular hours and even having to stay highly alert for transfer calls at night became the norm after they joined the battle against the virus.

After 14 to 16 busy days, they are switched with another batch of ambulance doctors and drivers. They are required to undergo a 14-day quarantine in a designated hotel before going back on call.

"It's a good chance to enjoy some downtime, exercise, watch TV, read books, and video chat with my family," Shi says.

As of Sunday, Tianjin had reported a total of 136 confirmed COVID-19 cases. Among them, 133 had been discharged from hospital after recovery, and three had died, according to the municipal health committee.

A total of 16 negative pressure ambulances, based at 11 medical emergency stations, have raced against the clock to transfer patients in Tianjin during the epidemic. Although the situation is improving, Shi, together with his colleagues, remains ready to leap into action whenever he is needed.

Sometimes, Shi's wife comes to the medical emergency station where he works and brings him some daily necessities. She puts the bag near the gate of the station. Shi will not take it until she steps back and maintains a certain distance. Unable to touch, they share an "air hug".

"It has been challenging over the past few months, but I will stay at my post until the end of the epidemic," Shi says.