Xiao Jinsong is racing against time to rescue survivors of last week's massive earthquake in southwest China, but he is not searching amid the rubble.
The doctor and his medical colleagues are trying to save those who escaped the quake alive but, officials say, now face a major risk of illness in makeshift tent cities.
They say the fight against contagious diseases is now a top priority almost one week after the 7.9-magnitude quake shook southwest China, leaving nearly five million people homeless.
Dujiangyan, a city of 60,000 people about 50 kilometres (32 miles) from the quake's epicentre, was one of the areas hardest hit by the disaster which the government estimates killed more than 50,000 people.
Temporary villages of dozens of lean-tos have sprung up on patches of grass in the city and around a key intersection. The communities lack running water and toilets, residents say.
Xiao, dean of the Dujiangyan Red Cross Hospital, said he and other doctors make regular inspections of the tent cities as part of measures to guard against disease outbreaks, which the World Health Organisation says pose the key threat after the quake.
"The water is clean but there are a lot of flies," Xiao said outside his hospital. He and his staff have set up an outpatient clinic under a tent beside the road rather than put patients and staff at risk of aftershocks inside the damaged hospital building.
So far, the biggest illness in the camps is the common cold, the doctor said.
In his white coat, Xiao said water-borne diseases are not a problem yet, and he and his colleagues from 12 hospitals in the area are monitoring camp conditions to ensure they do not become one.
"Unsafe food and lack of access to safe water, facilities for personal hygiene and safe sanitation arrangements all create a real risk of outbreaks of infectious diseases," said Arturo Pesigan, the WHO's technical officer for emergency and humanitarian action in the Western Pacific region.
Wei Chao'an, China's vice minister of agriculture, told a Beijing press conference on Saturday that combatting epidemics is "the most urgent and the biggest task facing us right now".
Water and food-borne bacteria and viruses are the main threat to public health in areas lacking basic facilities, such as cooking stoves and toilets, officials said.
"There's one toilet over there," said a woman at a tent village here, motioning towards a police station. "But it's too crowded so maybe some people go outside."
Volunteers deliver bottles of water every day, some of which a woman thrust upon visitors.
Some residents even sleep beside boxes of bottled water. Two large jugs hold their washing water, which they said they collected from a truck which arrived three days after the quake hit on May 12.
While the woman and her colleagues told their story near the pot where they cook under a tree, a volunteer arrived with leaflets that offered hygiene and health tips.
Similar leaflets have been distributed in the badly damaged city of Shifang, where soldiers were seen clearing garbage, and in isolated mountain villages.
Xiao said regular cleaning of roads and disinfecting is being conducted in a bid to maintain cleanliness.
Men carrying portable spray canisters were seen on the streets of Dujiangyan.
Housing Minister Jiang Weixin said heavy water purification machines were in Sichuan province or headed to hardest-hit Wenchuan and Beichuan counties, because air drops of millions of bottles of water were insufficient.
Each machine can produce enough safe drinking water for up to 10,000 people, said Li Dongxu, head of the housing ministry's urban construction department.