Michael Irving, 62 — a United States Marine veteran battling colon cancer — was enjoying a quiet night at his home in Theodore, Alabama, when he heard a “tap” on his door.

Naturally, he went up to the entrance, and answered it.

“I walked right here to open the door, and that’s when he shot me right there. They cut loose on me, and that’s when I went to the cabinet here and back behind the coffee was an old time pistol,” he told FOX-affiliate FOX10 News.

“I opened the door and smoked ’em.”

The intruders he detailed, according to authorities, were trying to rob him. Chasatie Dulabhan, Casey Ray Gann and Joseph Heathcock are the names. Irving managed to take down each one, injuring all three.

“I tried not to shoot any of them in the chest. I didn’t want to have to kill ’em.”

Investigators say the suspects left the scene after Irving opened fire, but were eventually nabbed by authorities at a Dollar General two miles down the road.

They were then taken to the hospital.

Irving — who’s being celebrated locally now — credits his background for being able to defend himself.

“I learned that in the Marine Corps — ‘react and do’ before you get scared.”

More from FOX10 News:

He was robbed a few weeks ago, targeted for his cancer medication. Deputies believe that robbery was committed by at least one of the same three suspects.

After that incident, Irving installed new Plexiglass on his door — something he believes helped save his life.

“Where the bullet hole is, you can see how thick that glass is and that’s what saved me, because it slowed down the buckshot enough.”

Irving says someone up above must have been watching over him.

“If I hadn’t of moved just a little bit, it would have hit me in the chest and sternum and caught me in the heart.”

All three robbery suspects are in Metro Jail.

Investigators say they’re looking into the possibility that there’s a fourth suspect, a getaway driver, who’s yet to be detained or charged.