Brendan Bialy helped disarm a school shooter in May. Now he is a United States Marine.

USA

Four months after leaping from his desk inside a STEM School Highlands Ranch classroom to help take down a shooter, Brendan Bialy is officially a U.S. Marine.

Bialy, who is from Castle Rock, graduated Sept. 20 from recruit training in San Diego.

In a video posted last week by the Marine Corps, Bialy said his thoughts about becoming a Marine “were nothing but reinforced after the shooting.”

“What I saw that day was complete and total malevolence — bad overcome by good,” Bialy said in the video. “And I lost an amazing person; the world lost an amazing person, Kendrick Castillo. However, I saw that benevolence won — legitimately and completely won in that situation.”

Castillo, 18, was killed when he, Bialy and Josh Jones rushed a shooter who was attacking their class on May 7. Jones and seven other students were injured. Two classmates face first-degree murder and other charges in connection with the shooting.

Bialy’s training instructor said in the video that the teen’s experience in the shooting became evident throughout his training.

“His past kind of reflected some of the things he had to do here,” the training instructor, who was identified only as Staff Sgt. Chestnut, said in the video. “Quick reaction, a willingness to fight. His character really showed.”

Brad Bialy, Brendan’s father, said his son joining the Marines reflects a “battle as parents.”

“You love your child more than anything else in this world,” the elder Bialy said. “But at the same time, knowing what he has to share, it’s not really our choice anymore.”

Gov. Jared Polis on Tuesday offered his congratulations on Facebook.

“He was already a hero and now he’s a Marine,” Polis said in the message.

A preliminary hearing last month for one of the school shooters shed light on the split-second decisions made by Bialy and other classmates and teachers when the shooters entered their classroom.

Kendrick Castillo was the first to rush one of the shooters, slamming him again the whiteboard. Bialy and  Jones joined the struggle, helping pry the gun away. Jones was shot twice in the leg but has recovered.

Bialy escaped unscathed, telling reporters in May that it must have been divine fortune.