Day or night, the doctors and medics of 1 Medical Squadron (1MS) at Sembawang Air Base (SBAB) are on standby to respond to aircraft emergencies and support search-and-rescue operations.
When activated, a two-man team - a medic and a medical officer - will be airborne within 15 minutes and ready to winch from a Super Puma helicopter hovering above sea: human lives literally on the line.
"It's quite exciting and very safe, as we're trained for this," said medical officer Captain (CPT) (Dr) Lester Leong, 30, who was once activated at 2am.
So was medic Corporal (CPL) Kenny Han, 22, who relishes the rare experience of flying in a helicopter.
They and their colleagues at 1MS, mostly fellow Full-time National Servicemen, perform such duties on top of attending to patients at the medical centre and hold regular drills to keep their skills current.
These sessions supplement the training they had received at the Singapore Armed Forces Medical Training Institute and help them counter the challenges of heliborne evacuation, which requires them to work swiftly and efficiently in a noisy and confined space.
Drills on winching and underwater evacuation form part of their training for search-and-rescue operations, conducted with other flying squadrons in SBAB.
This allows them to work smoothly with 125 Squadron in covering a 180-nautical-mile radius around Singapore.
Within this area, the 1MS crew is often the first to treat casualties and send them to the hospital. Casualties include civilians on commercial cruise liners and merchant ships.
"I think the Air Force's involvement in peacetime search-and-rescue operations adds a very meaningful dimension to what we do," said CPT (Dr) Leong.
"We have even helped people from other countries so in a sense, we're representing Singapore in a very personal way by doing our part in saving their lives."
Officer commanding CPT (Dr) Tan Jack Wei agrees. "When we are activated, it's usually for very severe and urgent cases," said the 28-year-old.
"What I do makes a difference in whether the patients survive, and I'm very blessed and very lucky to be able to perform this role."
CPT (Dr) Leong (right) and CPL Kenny Han during a recent heliborne evacuation.