Brown University student Joseph Oduro said he was in a lecture hall leading a review session for an upcoming economics final when a gunman wielding a rifle burst through the door and locked eyes with him.

"I immediately, when I saw him, I saw a gun," Oduro told ABC News correspondent Whit Johnson in an interview on Sunday. "The gun was so big and long that I genuinely thought, like, okay, this is the end of the road for me."

At least two people were killed and nine others were injured in Saturday's shooting, according to officials.

Police said the gunman fled the campus. A person of interest was detained and then released by police on Sunday. No charges have been filed yet in the case and police have not commented on a possible motive.

Oduro said he was in room 160 of the Barus & Holley building on the Providence, R.I., Brown campus with about 50 to 60 students when they suddenly heard a loud commotion, including what sounded like screams and gunshots, outside the door.

"And around five seconds or so later, we see a gunman walk in on the left-hand side," said Oduro, who said he's set to graduate this month.

Oduro said the gunman was dressed in dark clothing from head to toe and appeared to be wearing something that was bulging from his chest, saying it could have been ammunition or a bulletproof vest. He said the gunman was completely covered except for his eyes and part of a hand.

"We made eye contact," Oduro said. "I know he mumbled something, screamed something, I don't know exactly what was said, but he entered the room and you could just see the panic in all the students' eyes," Oduro said. "I was standing in the front so as soon as he walked in, he immediately saw me and I immediately saw him."

He said that as the gunfire erupted, he saw some students running out the door and others diving to the ground, "just whatever it takes to stay alive."

Oduro said he immediately dropped to the floor and motioned for students to take cover behind a table he was also hiding behind.

He said the gunman was about 30 feet from him at the top of the amphitheater-style lecture hall.

He estimated hearing forty to 50 gunshots and said some victims in the lecture hall were shot multiple times.

Oduro said he believes that all of the students who were shot in the incident were part of his review session.

Oduro said he texted his parents in what he thought might be his last message to them.

"I texted them, and I said, 'I love you all and I'm sorry for all the trouble that I put you through and I just love you all, and I'm thankful for all of your lives,'" Oduro said, showing ABC News the text messages.

Oduro said that while lying on the floor, petrified, he was simultaneously trying to comfort a student who had been shot in both legs and was in excruciating pain.

"If she were to make a noise ... anything like that and the gunman would have heard, we have no idea what would have happened. I think the state of emergency would have been way worse. So I gave her my hand to squeeze as hard as she could," Oduro said. "I said, 'Put all your pain on me because I could take it.'"

He said the time they were waiting for the gunshots to stop "felt like 14 days."

Oduro said that when the gunman left the room, he and other students still on the scene stayed put.

"You don't know if he's gonna come back, and the odds of him going to another room are extremely high. So, if we try and exit and find another way out, maybe we might cross paths with him again, and you can escape once, but you're definitely not gonna escape twice," Oduro reasoned.

He said that even when the police first entered the room and told students to put their hands up, no one moved.

"None of us complied because we all thought it was just another shooter," Oduro said.

Another Brown student, Ref Bari, told ABC News that he was inside the Barus & Holley building when the shooting broke out.

"The shots rang out behind me," Bari said.

Bari said he had just wrapped up a meeting with other students for a school project and was walking down a staircase to the first floor. He said he heard six or seven pops, but didn't immediately recognise the noises as gunfire, saying, "I've never heard anything like that in my life."

"I glanced behind me very quickly and the lobby of Barus & Holley was empty, or so it seemed," Bari said.

"In front of me, the ERC [Engineering Research Center], the like commons area of Barus & Holley is full with about a hundred students."

Bari said people were initially oblivious to the commotion, describing students wearing headphones as they prepped for final exams and projects.

"So, I'm thinking in that split second, 'Ok, maybe I misheard something. And then it just rings out, like pop, pop, pop again," Bari said. "And then I don't look back. I just run as fast as I can."

When people in commons area started realizing what was happening, they all started to rush for one of two exits, Bari said.

"So, imagine a hundred kids trying to rush out through two exits," Bari said.

He said he didn't notice anyone screaming or panicking: "It's just silence and gunshots behind us," Bari said.

Bari said that when he got outside, he called his parents as he continued to run across the street to the science library.

"Folks coming out of the science building had no idea what was going on. So, as I was running, I started shouting, 'Active shooter! Run!'" Bari said.

He said he was planning to run to his apartment, but ran into a friend who invited him and other students to shelter in place at her apartment.

"We hid in her bathroom for like two hours, four of us in a small bathroom for two hours," Bari said. "And it was terrifying, but I think, thanks to her, I'm alive right now."