While authorities investigated, teachers and students huddled together in locked rooms, said Marianna Sviland, a teacher at the college who was in a faculty workroom at the time of the stabbing.
"Outside the window, I saw cops running around, I saw students running and I realized something was going on," she said. "It was scary."
By 2 p.m. (3 p.m. ET), students and staff were allowed to leave campus, Sviland said.
Details about the victim's injuries were unclear Tuesday afternoon.
Bernstein said it wasn't clear whether all of the injured people were stabbed.
"It's possible other people were running away" and became injured that way, he said.
Four injured victims "were in a dire enough situation that they were taken out on helicopters," Bernstein said.
"I do believe the confrontation was limited to a few (classrooms) or just one classroom -- not anybody roaming around and getting into a large number of areas," Bernstein said.
The school posted a warning on its website: "Stay away from the area. Seek shelter in a secure location until the incident is resolved."
The campus was scheduled to reopen for classes Wednesday morning. Officials said counselors would be speaking with faculty and students.
Tuesday's incident comes more than two months after three people were wounded in a shooting at a different Lone Star College campus -- the North Harris campus in Houston.