An armed father saved the day when he stopped what could have been a mass shooting inside an Alabama McDonald's on Saturday.

The unidentified father was leaving the popular fast food chain when a masked man walked in the restaurant behind him and started shooting.

The father immediately pulled out his own weapon and returned fire at the suspect — and became the shooter's own target. The father and his son sustained injuries, while the gunman died from his wounds during the incident.

Authorities are not yet sure what the gunman's motive was — whether to rob the McDonald's or shoot someone at the fast food restaurant.

The hero father sustained life-threatening injuries, and his son is also recovering from gun-related wounds. No one else at the establishment was injured thanks to the quick reaction of the unidentified father.

Markus Washington, an employee at the McDonald's location, told WBRC-TV that he was making quarter-pounders as the bullets began flying. He ran into the freezer for safety.

"I'm feeling grateful," he told the station. "Wrapping my head around it all, I was just wishing someone would come wake me up from this nightmare."

Behind the freezer door, Washington could hear gun shots, and ultimately feared the worst had happened.

"All we hear is like different gunfire, so in my mind, I'm imagining everybody is dead. He's looking for us," he said.

Washington also explained that he was thankful the armed customer was there, "He's my hero. Because I can only imagine how it would've went if he wasn't armed. We might not be here having this interview," he said.

The father is not expected to face charges as he was protecting the other customers and employees at the McDonald's.