HIGHLANDS RANCH, Colo. -- Brendan Bialy said he was sitting in class at STEM School Highlands Ranch on Tuesday afternoon when another student showed up late and pulled out a gun.
What happened next, Bialy said, was an "immediate, non-hesitation jump into action."
Bialy, along with classmates Kendrick Castillo and Joshua Jones, charged the suspected shooter against a wall and disarmed him, Bialy said Wednesday at a news conference.
In the skirmish, Castillo, an 18-year-old senior just days away from finishing high school, was fatally shot. Jones was shot twice and was recovering on Wednesday, according to his family, which confirmed in a statement that Jones was involved in disarming the suspect.
Jones' spoke to ABC's Good Morning America on Thursday, describing what happened.
"We rushed him. Kendrick pushed him against the wall me and Brendan grabbed him and threw him to the ground. I stayed on top of him while Brendan went off and tried to help Kendrick," he said.
After Castillo was shot, Bialy said he kept the gun away from the suspect and helped a teacher perform chest compressions on Castillo. But Castillo didn't respond.
On Wednesday, the teenager who was a member of the school robotics club was being remembered as a hero.
"He charged the shooter and was immediately on top of him," said Bialy, a senior at the STEM school who is joining the Marines. "He was ready to end the threat."
In a news conference earlier Wednesday, Douglas County Sheriff Tony Spurlock said there were "very heroic things that took place" at the school Tuesday and said at least one student encountered the suspects and worked to stop them. Spurlock said he had also reviewed video from inside the school showing other heroic acts involving Douglas County deputies and staffers
Spurlock described the incident between the student and the alleged shooters as an "encounter" but said he could not elaborate further.
In the classroom, Bialy said he was sitting in a desk on the left side of the room, near where the alleged shooter walked in. Jones said they all had a choice to make "that no one should have to make." Castillo was also near the suspect and sprung into action.
"It's very hard to stop that kid when he gets going," Bialy said. "The gunman was there, and then he was against the wall and didn't know what the hell hit him."
Castillo's parents said they've heard stories from other students about their son's actions, how he rushed the shooter and saved lives.
"I loved him and he's a hero," his father, John Castillo, said. "He always will be. But there's another part of you that just wishes he ran."
Bialy said he "couldn't be more thankful that Kendrick did what he did."
"Kendrick went out as a hero," Bialy said. "He didn't go running. I'm not saying anyone who ran was a coward. But Kendrick was there. He was a foot away from the shooter, and instead of running the opposite direction, he ran toward it."