Ryan Folkes and his friends from CFB Gagetown were driving on the Trans-Canada Highway east of Badger around 4:30 p.m. Sunday when they spotted an overturned truck in the ditch.
The group saw flames coming from the truck when they pulled over to investigate.
"Me and the boys, we started to hear some of these panicked cries, 'She's stuck in the vehicle, she's stuck in the vehicle,'" Folkes said.
Folkes said they split into two groups — one to direct traffic and another to fight the fire — while the other one helped the injured woman stuck inside the truck.
They managed to free the seriously injured woman, carrying her to a safe distance on an impromptu stretcher.
"We actually used a road sign from the side of the highway [and] we carried her off to a safe area because we didn't know when this truck was gonna blow, and not three, maybe four minutes after we got the casualty out, the whole vehicle exploded," he said.
The group helped control the woman's bleeding until an ambulance arrived on the scene.
Ryan Elliott, one of the people in the group, said there was never a second of hesitation to jump into action.
"I guess the one thing the military has taught us quite well is, they put you through a lot of stressors, they make things very, very difficult, so that one day, when it is difficult, it's easy," said Elliott.
The woman was taken to hospital with broken bones and other serious injuries.
The cause of the accident is still under investigation by police.