(NewsNation) — When security officers spotted an armed man inside a Houston mall on Feb. 5, Sgt. Kendrick Simpo took swift, but silent, action.

Simpo, a Houston police officer who was working an extra job at the Galleria mall, was on the opposite side of the mall when Guido Herrera was seen heading toward a group of children armed with a rifle.

Not wanting to frighten the children, Simpo kept his weapon holstered as he approached Herrera.

“I played it off like I didn’t see him, and as we got side by side, I kind of bum-rushed him and tackled him,” Simpo said Tuesday on NewsNation’s “Rush Hour.”

While the encounter happened months ago, Simpo’s recounting to NewsNation comes after an armed civilian shot and killed a gunman at an Indianapolis mall on Sunday. The gunman, Jonathan Sapirman, killed three people and injured two more before he was shot dead by the bystander, Elisjsha Dicken.

No shots were fired during the mall incident in Houston, but Simpo said he was mentally prepared to get wounded during his struggle with Herrera.

“You just got to have that mindset that you’re going to win no matter that the cost is,” Simpo said. “Deep down I knew that I was in the fight for my life, and I wasn’t going to give up.”

When police arrested Herrera, he had 120 rounds of ammunition and was wearing a leather mask with spikes. Because no shots were fired, Herrera was charged with a misdemeanor.