FORT HOOD, Texas — Pfc. Marquest Smith, on his way to Afghanistan in January, was completing routine paperwork Thursday when the sounds erupted.

A loud, popping noise. Moans. The sudden, urgent shout of “Gun!”

Smith poked his head over the cubicle's partition and saw an Army officer with two guns, firing into the crowded room.

The 21-year-old Fort Worth native quickly grabbed the civilian worker who'd been helping with his paperwork and forced her under the desk.

After the shooter stopped to reload, Smith made a run for it. Pushing two other soldiers in front of him, he made it out of the Soldier Readiness Processing center — only to plunge into the building twice more to help the wounded.

Smith had survived the worst mass shooting on an American military base, a rampage of more than 100 shots that left 13 dead and 30 wounded, including the alleged shooter, Army psychiatrist Maj. Nidal Malik Hasan.

It could have been much worse, but for the heroics of Smith and others — like the 19-year-old private who ignored her own wounds, and the diminutive civilian police officer whose gunfire helped take down Hasan.

Home of the 1st Cavalry and 1st Army Division West, Fort Hood has seen more than its share of deployments and casualties in the past eight years.

As a psychiatrist, Hasan, 39, had listened to soldiers' tales of horror. Now, the American-born Muslim was facing imminent deployment to Afghanistan.

In recent days, Hasan had been saying goodbye to friends. He had given away many of his possessions, including copies of the Holy Quran.

Thursday morning, surveillance cameras at a 7-Eleven across from the base captured images of a smiling Hasan, dressed in a long white garment and white kufi prayer cap, buying his usual breakfast — coffee and a hash brown.

At the processing center on the southern edge of the 100,000-acre base, soldiers returning from overseas mingled with colleagues filling out forms and undergoing medical tests in preparation for deployment.

Around 1:30 p.m., witnesses say a man later identified as Hasan jumped up on a desk and shouted the words “Allahu akbar!” — Arabic for “God is great!” He was armed with two pistols, one a semiautomatic capable of firing up to 20 rounds without reloading.

Packed into cubicles, the 300 unarmed soldiers were sitting ducks.

When he decided that Hasan wasn't close to being out of ammo, Smith made a dash for the door. He'd made it outside when he heard cries from within.

“I don't want to die.”

“This really hurts.”

“Help me get out of here.”

Smith rushed back inside and found two wounded. He grabbed them by their collars and dragged them outside.

His second time through the door, he ran into the shooter, whose back was to him. Smith turned and fled, bullets whizzing by his head as he rushed outside.

Around this time, Fort Hood Police Sgt. Kimberly Munley got the call of “shots fired.” The SRP isn't on Munley's beat; she was in the area because her vehicle was in the shop.

Munley, 34, was on the scene within three minutes.

Just over 5 feet tall, Munley is an advanced firearms instructor and civilian member of Fort Hood's special reaction team. She had trained on “active shooter” scenarios after the April 2007 mass shooting at Virginia Tech University. She didn't wait for backup.

As Munley approached the squat, rectangular building, a soldier emerged from a door with a gunman in pursuit. Munley fired, and the uniformed shooter wheeled and charged.

Another officer, Senior Sgt. Mark Todd, also responded to the sound of gunfire. He arrived to find Hasan “just standing there, hiding behind a telephone pole.”

“He just looked like he was calm … it was almost like he was pointing his finger at me,” Todd said Friday. “But then I seen the weapon. ... and muzzle flashes and then that's when we returned the fire.”

Munley was hit at least three times in the exchange — twice through the left leg and once in her right wrist. Hasan was hit four times. It's not clear whose bullets hit the suspect, but from the first shots to the last, authorities say the whole incident lasted less than 10 minutes.

Bloodied soldiers, some shirtless, treated each other on the grass outside, ripping pant legs off and tying off wounds. Munley was loaded into an ambulance.

Pfc. Amber Bahr, 19, of Random Lake, Wis., tore up her blouse and used it as a tourniquet on a wounded comrade. It was only later that she realized she'd been shot in the back, the bullet exiting her abdomen.

Hasan lay on the ground, his two handguns beside him, as medical personnel struggled to remove his handcuffs to treat his wounds.

Sgt. Howard Appleby, 31, was at the hospital for his regular meeting with a psychiatrist. Appleby, who was born in Jamaica and grew up in New York City, sustained a traumatic brain injury and has post-traumatic stress disorder from a roadside bomb blast during a tour in Iraq.

His appointment canceled, Appleby found himself pulling the dead and wounded from ambulances. In combat, he was used to one or two casualties a day. “This,” he thought, “is crazy.”

For several hours, authorities feared there were several gunmen. By the end of the day, it was clear Hasan had acted alone, they said.

Hasan, hooked up to a ventilator, was moved Friday to a military hospital in San Antonio. The woman who stopped him, Munley, awaited surgery Friday to remove the bullets from her leg.

Her boss, Chuck Medley, was thankful.

“If an officer had to be close by to respond,” he said, “Kim Munley is someone we'd want to be there.”