Fort Hood, Texas (CNN) -- Pvt. Joseph Foster was filling out routine paperwork for his upcoming deployment to Afghanistan on Thursday when he heard a shout quickly followed by a burst of gunfire from just a few feet away.
"I was sitting in about the second row back when the assailant stood up and yelled 'Allahu akbar' in Arabic and he opened fire," Foster said Monday on CNN's "American Morning."
Foster, 21, did not forget his basic training, which may have saved his life and the lives of others.
"[I] got down on the floor, moved to cover. One soldier had peeked his head around the cubicle I was hiding in ... and I pulled him in," Foster said. Foster realized he had been shot in the hip but was too consumed by adrenaline to think about his injury.
"Another soldier had come in as soon as the assailant had moved away from us," he said. "Those two got up and got out, and I got out shortly behind him."
Once outside, Foster said, he hid behind a military shipping container "and started doing what I was trained to do."
"[I] started helping get people into the next building and get them under cover," he said.
Despite his injury, Foster, who has a wife and two young children, said he still plans to deploy to Afghanistan in January.
"I'm still a soldier day in and day out," he said. "I'll do my job."
Authorities are trying to figure out what prompted the gunman to begin shooting at Fort Hood Army Post, killing 13 people and wounding 42. Fifteen soldiers are still hospitalized, including eight patients in intensive care, Fort Hood commander Lt. Gen. Robert Cone said Monday.
Maj. Nidal Malik Hasan, a 39-year-old licensed Army psychiatrist who worked at a hospital on the post, is the suspected shooter. He was shot several times, ending the attack, and is now conscious and talking, a spokesman at Brooke Army Medical Center in San Antonio said Monday.
It is unclear if Army investigators have spoken to Hasan.
The intense investigation into the mass shooting remains largely shrouded in silence. Army officials have voiced concern about jumping to any conclusions about the motive, warning about a possible backlash against Muslim soldiers. Several bystanders, like Foster, reported Hasan shouted "Allahu akbar," Arabic for "God is great," which terrorists have used as a battle cry.
The Army leadership at Fort Hood will "take a very hard look at ourselves and look at anything that might have been done to have prevented this," Cone said Monday.
"Hasan was a soldier, and we have other soldiers ... that might have some of the same stress and indicators that he has," Cone said. "We have to look across our entire formation, not just in a medical community, but really look hard to our right and left. That's the responsibility for everybody, from the top to the bottom, to make sure we're taking care of our own."
Cone said Monday that he has instructed commanders at Fort Hood to "immediately take a hard look and make sure if there's anybody out there struggling [that] we're going to address their issues."
Sen. Joe Lieberman said he plans a Senate committee hearing into whether the shootings were a terrorist act and whether the Army should responded to reported signs of Islamic extremism by the suspected gunman.
If Hasan was showing signs of being an Islamic extremist, the Army should have acted on that earlier, and "he should have been gone," said Lieberman, a Connecticut independent and chairman of the Senate Homeland Security and Governmental Affairs Committee. He spoke on "Fox News Sunday."
The shooting, on the nation's largest military base, sparked outrage. In his Saturday radio address, President Obama said it was "an act of violence that would have been heartbreaking had it occurred any place in America."
But, he said, "it's all the more heartbreaking and all the more despicable because of the place where it occurred and the patriots who were its victims."
All but one of those who were killed were soldiers.
Obama and first lady Michelle Obama will attend a Tuesday memorial service for the victims. Defense Secretary Robert Gates will also participate in the memorial service, but he will not speak, Pentagon spokesman Geoff Morrell said.
Gates on Monday night will go to Fort Hood, where he will meet with the victims' families as well as Fort Hood Police Sgt. Kimberly Munley, the civilian officer who confronted and disabled Hasan as they shot at each other.
Gates will also meet with military officials at the Army base, including Fort Hood's commanding general, Lt. Gen. Robert Cone, and Chairman of the Joint Chiefs of Staff Adm. Mike Mullen, according to Morrell.
CNN's David Mattingly and Victor Hernandez contributed to this report.