On a day in late December, Gabriel McInnis — a sergeant in the Marine Corps Reserve — was driving through a residential area, on his way to perform his duty within a funeral honors detail when he heard something.

It was a something that simply wasn’t right. Something that didn’t sit well with him. A sound that kept him from passing through the Phoenix, Arizona neighborhood altogether.

“I was approaching a light, when I heard some screaming and yelling,” the service member told the USMC website (McInnis serves as an engineer equipment mechanic with Bulk Fuel Company C, 6th Engineer Support Battalion, 4th Logistics Group.

He soon discovered the alarming situation: a big guy in an open doorway “physically assaulting Tia Simpkins and her family” — in their own home.

“I knew I had to act. I threw my car in park and ran over to try and stop it.”

From the Marines:

He tackled the attacker despite being outclassed in height and weight. Soon the pair was on the ground exchanging blows. Although McInnis took a lot of punches, he prevented the attacker from getting to the family.

“Finally, I catch a lucky break,” McInnis said.

The attacker threw a punch, missed, and fell to the ground. McInnis used the opportunity to perform an arm-bar takedown, a martial arts move, to subdue his opponent. After restraining the attacker, he dialed 911 and the police responded within minutes.

By putting his own welfare on the line, McInnis was able to prevent the assault against Simpkins and her family.

“I know he is a true hero because there is no way he could have had time to consider his own safety,” Simpkins said.

Where did McInnis learn the karate move? Why, the Marine Corps Martial Arts Program, of course. He’s actually an instructor.

For his heroic actions, McInnis was recently awarded the Navy and Marine Corps Achievement Medal by his unit.

“I joined to help people and I’ve had a few opportunities to do it,” he said.

And he’s not kidding. Just a couple of years ago, the Marine helped save a woman on a plane to Hawaii after she had lost consciousness due to diabetic shock.