Then screaming, panic and pain.
“I lifted my left hand and felt my fingers hanging off, tapping against the back of my hand, which was just a bloody stump,” remembers JJ Chalmers.
“And my right arm was gone, it just wasn’t there. That’s when I realised there was nothing I could do for myself, other than call for help.
“That’s when I started thinking ‘oh man, what have you got yourself into here?”
A massive commotion was going on all around. Blood, dust, fear.
Eventually someone arrived to help and patch him up, before having to go and help other casualties.
Two of his fellow marines had been killed, along with their Afghan interpreter.
“It was the scariest thought in the world, being alone,” Chalmers admits.
He was only thinking of survival until he heard the unmistakeable, heavy whirr of a helicopter overhead, and at that point he knew he wouldn’t die on that patch of ground.
John James Chalmers, 23. He had been a Royal Marines commando.
The best of the best, the elite. Doing a job he loved, alongside men he admired, pushing himself to the absolute limit, each and every day.
A few days later, he was lying in his bed in hospital. The right side of his face had almost collapsed; he had lost two fingers and had the others wired back on; his right elbow had disintegrated; his legs were badly injured.
“I was lying there thinking ‘what’s to come? What is ahead of me?’”
Screaming in the dark
Senior aircraftman Mike Goody was having to live at home with his parents again after being blown up by a roadside bomb in Kandahar, Afghanistan, in August 2008.
Mike Goody was trapped under his vehicle for four hours The 22-year-old had been trapped under the wreckage of the armoured vehicle he was driving for four hours, before eventually being pulled free.
After that there were 14 operations to save his lower leg, but they were in vain and it had to be amputated. He was also suffering from post-traumatic stress disorder and terrifying flashbacks.
It was an incredibly tough time for both him and his parents, Frank and Jackie. His mum Jackie remembers one particularly vivid night.
“Mike was in his bedroom and you could hear him screaming and shouting and banging on the door, speaking some bizarre language I later found out was Pashto, which he’d learnt out there,” she recalls.
“It was just a case of trying to calm him down and talk to him.”
Goody was struggling to cope though and sought solace in alcohol.
“A typical day for me would be waking up from an epic day’s drinking, cracking my first beer open within 10 or 15 minutes, then onto the next and the next,” he remembers.
“Then it was onto the spirits. Then I’d be thinking ‘how can I successfully kill myself?’ Not just a fleeting thought, but in-depth planning.
“I felt like I was a burden. If I wasn’t here, I wouldn’t be a burden any more.”
'Competitive beast' is back
Like many other injured servicemen, corporal Paul Vice was taken to the military rehabilitation centre at Headley Court in Surrey.
That’s where the possibilities offered by sport opened up in front of him.
Wheelchair tennis, swimming, athletics – he tried them all, before deciding he liked sitting volleyball, cycling and archery best of all.
His injuries were numerous and severe after he was blown up by an IED, or improvised explosive device, in Afghanistan in August 2011.
He reels them off: “Four hundred significant wounds up and down my left side, quite a bad head injury, severed carotid artery.”
Vice, now 31, can still clearly remember the explosion that tore him apart three years ago.
"I was walking along on a normal day patrol," he says "and saw two guys hunkered down in a field.
"Then I saw an oil drum poking out of the bottom of a wall. I knew what it was and ran, but not fast enough. I turned round and that was it. Boom. Game over."
Not quite game over though.
The sight of Vice pulling the cord of his bow using his mouth during an archery session shows his ingenuity and determination to overcome his injuries.
“Just because you are down, doesn’t mean you are broken or beaten and can’t compete,” Vice says. “Any marine is a competitive beast and you have to get back to that as quickly as possible.”
Rock stars take to the stage
Sport also rescued Goody, providing a salvation from alcoholism and suicidal thoughts.
He competed in a marathon and iron man competition and was within a whisker of being chosen for a trek to the South Pole with Prince Harry.
Then he rediscovered his love of a swimming.
As a teenager, Goody had competed in galas up and down the country and even hoped to compete in the Olympics one day, although he ultimately lacked the dedication to realise his dream.
Now he is giving the sport his all and has been selected to compete for Britain at the Invictus Games.
For Chalmers, sport reminded him what he was capable of.
“Not being arrogant, but I didn’t used to be an average human being,” he says.
“I was a Royal Marines commando. I was capable of a whole lot and pushed myself to the absolute limit. But in the past few years, to keep my head above water, the average became acceptable.
“Once you get involved in sport, you realise you are capable of a whole lot more.”
He took up cycling, got better and better, and started to compete.
“Getting on that bike, doing 45km and enjoying the pain and punishment and looking forward to getting back on and doing even better next time – that’s how I used to feel before I was injured,” he beams.
He has been selected by Britain for non-amputee cycling and will compete at the Lee Valley Velopark on Saturday September 13th.
Britain's captain for the Invictus Games is Dave Henson MBE, who will be competing in sitting volleyball, as well as the 200m and 400m.
The 29-year-old, who was blown up by an IED while serving with the Engineer Regiment in Helmand in February 2011, says the Games will be a chance to “come together and show we can’t be overcome or beaten”.
“And in front of everyone we care about,” he adds.
Goody is relishing the chance to “prove to myself and my parents and family that I can do stuff”.
His dad, Frank, a former military man himself, is not prone to outpourings of emotion, yet he admits it could be difficult to keep himself together when his son competes.
“I was terrified when I first saw his injuries,” he admits. “I wondered ‘will he cope?’ And, yes, he did cope. What holds him back? Nothing. He will go for everything.”
The Games will also provide an opportunity for the men to stand alongside their former colleagues once more.
“The thing I am looking forward to most of all is getting in amongst the lads again,” Chalmers says. “They’re the same sort of friends I had in Afghanistan.
"This group of people I am just honoured to know. They are my inspiration and should be everyone’s inspiration.
“The guys are rock stars and should be the most famous people in the world.”