Lone Star student Daniel Flores, 19, said he was in a tutoring lab on the second floor doing homework when he heard what he heard six to seven shots.
"I didn't think they were shots," he said. "It sounded like someone was kicking a door."
About 60 people were in the lab, and they began running out of the room once they realized the sound was gunfire, he said. They fled to a nearby student services center, where authorities kept them there for about 30 minutes before letting them go.
Associated Press writer Eileen Sullivan contributed to this report from Washington.