Three Americans say they relied on gut instinct and a close bond forged through years of friendship as they tackled a heavily-armed man on a train speeding through Belgium.
US Airman Spencer Stone said the gunman, an assault rifle strapped to his bare chest, seemed like he was "ready to fight to the end". But he added: "So were we."
His arm in a sling, Mr Stone, 23, said he was coming out of a deep sleep on the Amsterdam to Paris train on Friday when the gunman appeared.
One of his friends, Alek Skarlatos, a 22-year-old National Guardsman recently back from Afghanistan, "hit me on the shoulder and said 'Let's go'."
French President Francois Hollande is to present the Americans with the prestigious Legion of Honour tomorrow.
A French citizen who first came across the gunman near a train bathroom and a British man who joined to help tie up the assailant also are being honoured with the award, according to the president's office.
The gunman, identified as 26-year-old Moroccan Ayoub El-Khazzani, is detained and being questioned by French counter-terrorism police outside Paris.
French and Spanish authorities say El-Khazzani is an Islamic extremist who may have spent time in Syria.
El-Khazzani's lawyer said that he was homeless and trying to rob passengers on the train to feed himself.
Authorities in France, Belgium and Spain, where he once lived, are investigating the case. French authorities can legally hold him for questioning until Tuesday, when they must charge him or free him.
Mr Skarlatos said El-Khazzani "clearly had no firearms training whatsoever," but if he "even just got lucky and did the right thing he would have been able to operate through all eight of those magazines and we would've all been in trouble, and probably wouldn't be here today, along with a lot of other people".
Military training "mostly kicked in after the assailant was already subdued," Mr Skarlatos said. "We just kind of acted. There wasn't much thinking going on," he said.
The pair moved in to tackle the gunman and take his gun. The third young man, Anthony Sadler, 23, moved in to help subdue the assailant. "All three of us started punching" him, Mr Stone said. Mr Stone added he choked him unconscious.
British businessman Chris Norman also joined in the fray.
Married grandfather-of-two Mr Norman said he helped overpower the gunman because he thought he was "probably going to die anyway".
Mr Skarlatos thanked Mr Norman for helping to tie the gunman up after he had been overpowered.
Mr Stone, of Carmichael, California, spoke at a news conference at the US ambassador's residence in Paris along with Mr Sadler, a senior at Sacramento State University in California, and Mr Skarlatos, of Roseburg, Oregon.
Mr Stone is also credited with saving a French-American teacher wounded in the neck with a gunshot wound and squirting blood.
He said he "just stuck two of my fingers in his hole and found what I thought to be the artery, pushed down and the bleeding stopped". He said he kept the position until paramedics arrived.
El-Khezzani boarded in Brussels with what France's interior minister said was an arsenal of weapons that included an automatic pistol, numerous loaded magazines and a box cutter.
He was subdued while the train travelled through Belgium, but was taken into custody in the northern French town of Arras, where the train was rerouted.
El-Khezzani's lawyer said her client does not understand the suspicions, media attention or even that a person was wounded. For him, there were no gunshots fired, Sophie David said.
"He is dumbfounded that his action is being characterised as terrorism," she said.
He claims to have found the weapons in a park near the Brussels train station where he had been sleeping, stashed them for several days and then decided to hold up train passengers.
"When most of us would run away, Spencer, Alek and Anthony ran into the line of fire, saying 'Let's go'. Those words changed the fate of many," US Ambassador Jane Hartley said.