Last Updated Aug 22, 2015 7:58 PM EDT
ARRAS, France -- It sounds like something out of a Hollywood thriller but stars three very real American heroes.
One is an Air Force airman, another an Army National Guardsman. The third is a pal from California.
The trio was on a high-speed train from Amsterdam to Paris on Friday when a gunman opened fire. The suspect is known to intelligence services in three countries for possible links to radical Islamic groups.
That's when the three Americans jumped into action.
Video that appears to be shot inside the train shows the suspect face-down and tied up. You can see a rifle he was carrying and one of the American men who brought him down.
After seeing a French passenger first confront the gunman, 22-year-old National Guardsman Alek Skarlatos and his two friends moved in.
"I saw a guy entering the train with an AK and a handgun, and I just looked over at Spencer and said, 'Let's go. Go,'" Skarlatos said. "And he jumped up, and I followed behind him by about three seconds."
U.S. Air Force Airman 1st Class Spencer Stone tackled the gunman, and Skarlatos knocked him unconscious with the butt of his rifle.
Fellow friend Anthony Sadler and British passenger Chris Norman pinned the attacker down and stripped him of his weapons.
CBS News caught up with Norman outside the police station in Arras to ask why he chose to move forward rather than hide.
"What else is there to do? Either you sit down and you die, or you get up and you die," Norman said.
Stone was released from a French hospital Saturday afternoon. The gunman sliced into him with a box cutter, almost cutting off his thumb. But even wounded, friends say Stone treated others.
"A man's throat had been slit," Sadler said. "And he was bleeding profusely, and Spencer, who has some paramedic training, just clogged up his neck so he wouldn't die."
Skarlatos' parents, Karen and Emanuel from Roseburg, Oregon, said they never doubted the young men's courage.
"The fact that they saved all those lives and had that instinct and the guts to just do what they did ...," Emanuel Skarlatos said.
When police arrested the gunman at the next stop, they found an arsenal: an assault rife, a handgun and several magazine clips.
The 26-year-old Moroccan suspect, identified by French media as Ayoub El-Khazzani, was on the terror watch list of three countries, including France. The French interior minister confirmed the suspect has been on their radar since a tip from Spanish authorities.
Despite that, he was able to board a high-speed train armed to the teeth apparently bent the massacre of civilians.
But he picked the wrong train.