Inside the Attack on Paris-Bound Train: The Timeline of Terror

Alek Skarlatos said the first thing he heard was a gunshot.

Here is an inside-look at the apparent timeline of terror on board the train Friday, according to the passengers.

A gunshot:

National Guardsman Alek Skarlatos, 22, of Roseburg, Oregon, said the first thing he heard was a gunshot.

His friend, Airman 1st Class Spencer Stone, 23, of Carmichael, California, said the sound woke him up from "a deep sleep." When he turned and saw the gunman, identified by French authorities as Ayoub El-Khazzani, his first thought was about "survival, to survive and for everyone on the train to make it."

An American takes action:

American Mark Moogalian was the first person to disarm the gunman, according to a statement Sunday from Moogalian's family.

"When the gunman came out of the bathroom another person engaged him and was thrown to the side, Mark then jumped in and after a struggle was able to get the AK-47 away," the statement said.

"Mark then turned around to get his wife out of harm’s way but did not realize the gunman still had a pistol," the statement added. "He shot Mark in the back, the bullet went through his lung and exited his collarbone. When Mark went down that’s when the gunman retrieved the AK-47. Mark was able to get to another car and that's when other(s) rushed in."

Three friends rush in:

"Alek just yells, 'Spencer go!'" Skarlatos and Stone's friend Anthony Sadler said.

"And Spencer just gets up within five seconds of the guy being in the car and just rushes back there," Sadler, 23, a senior at Sacramento State University in California, said. "He gets up, I get up and Alek gets up and all three of us just rush back there."

Stone tackled the attacker to the ground, Sadler said. As Sadler, Skarlatos and a fourth passenger, British businessman Chris Norman, jumped in to hold him down, the attacker pulled out a box cutter and slashed Stone, Sadler said.

“He seemed like he was ready to fight to the end," Stone said. "So were we."

Stone said he choked the attacker unconscious while Skarlatos hit him in the head.

Once the gunman was hogtied on the floor, Stone went to help Moogalian, who was also injured. Stone said he used his fingers to stop bleeding in the Moogalian's neck.

An attacker in custody:

El-Khazzani’s first lawyer, Sophie David, told ABC News in a phone interview that El-Khazzani denied planning an attack and said he wanted to rob passengers and escape by jumping off the train. The suspect also denied any ties or affiliation to terror groups or radical Islam, David said.

A medal from France:

Skarlatos, Sadler, Stone and Norman received France’s highest medal at the Elysee Palace today, making them Chevalier, knights of the Legion of Honour.

Two other passengers, Moogalian and another person who wished to remain anonymous, will reportedly be honored at a later time.

Moogalian remains in intensive care today, according to the Centre Hospitalier Régional Universitaire de Lille.

The Associated Press contributed to this report.