 -- An American doctor who was dropping her friend off at the airport found herself rushing into action and using office supplies to save lives in the moments after the bombing at the Brussels airport.

Dr. Laura Billiet, an internal medicine physician, was dropping off her friend, Laura Harper, when they heard the first bomb go off Tuesday morning, said Billiet, who has been living in Belgium temporarily with her family.

At first both Billiet and Harper did not understand what had happened immediately after the attacks, Harper said.

"It was very surreal. It was not that loud of a sound," Harper told ABC News. "At first I wasn’t concerned and then I thought, 'Wait, that doesn’t make sense. Why would I hear that?' When I turned around, I saw glass and dust billowing out. I said, 'That was a bomb.'"

Billiet said she didn't realize what had happened until Harper told her it was a bomb and they needed to try and drive away. But since all the other vehicles were trying to leave as well, they were suck near the airport as the second bomb went off, showering the area nearby in glass.

"She said, 'It’s another bomb. Let’s get out and run,'" Billiet said of Harper. "We got out of the car and started running."

Eventually they found shelter in a nearby police station. The police quickly left to investigate what had happened and they were left virtually alone in the police station as waves of injured people started to arrive, Billiet said.

"She started to triage," Harper recalled of Billiet. "She said, 'There’s people hurt. I’m going to go help those people.'"

Harper said at first nauseated and scared by the sight of the injuries, which included shrapnel wounds and signed hair. However, both she and Billiet quickly jumped into action.

"It still felt unsafe. We kept waiting for the other shoe to drop," Billiet recalled, saying she thought there might be a gunman or another bomb. "Then we started to see children coming in who were injured. We started working on, trying to help people and we didn’t have a lot of things to work with."

Billiet said she found some paper towels and a pair of scissors that she used to cut away clothing and find injuries. A basic medical kit they found did not have antiseptic or burn salve, she said.

"The first airport employee I saw -- all her hair had been singed off on one side, she had shrapnel in her face and blood all down her shirt and her pants were soaked in blood," Billiet said. "I cut the pants off her and she had lots and lots of shrapnel wounds in her leg that were bleeding. A lot of people looked like that, some kids -- that was the hardest thing to see for us."

Even in the chaos as more and more people arrived, Billiet said she was struck by how many people were thinking of others and asked her to look at someone with worse injuries than their own.

"A lot of people said, 'No, no, I can wait. Look at him first or look at her first," Billiet recalled. "That was nice to see."

Some people were in shock and didn't realize the severity of their injuries, she said.

Harper also jumped into action to help the injured. Two young girls who were injured were screaming after losing track of their parents, she said.

"I just looked at them and thought of my own daughters. I was singing. I tried to get them to sing with me," Harper said. "The younger one was really shaking and going into shock."

Billiet said without further help it was crucial that Harper sat with the two girls, who were injured by the blasts.

"I think those girls needed someone with them and there wasn’t anyone available to speak their language," Billiet said. "She really did a good service and thank God because there were so many people there that needed things and so little that we had to give them."

Eventually paramedics came to take the wounded to area hospitals after rushing into the damaged airport, Billiet said.

The two women, who said they have been best friends since elementary school, are now back in Brussels and Harper said she is looking to find a flight back to the U.S. Billiet said she and her family had been planning to move back to the U.S. on Sunday, but are not sure now when they'll be able to get back to the states.