NASHUA, NH (CBS) – His shift this past weekend started as it had for the past 10 years.

“It was a normal Sunday shift… Sunday into Monday 11 p.m. to 7 a.m.,” said Shannon Cothran, a clerk at the Shell on Main Street in Nashua, New Hampshire. Then around 3 a.m. Monday morning, a man rushed in yielding a knife.

“He was very heavily masked and clothed. He came directly in and produced a knife and came around the corner and threatened my life,” he said.

Surveillance video from the store backs him up. You see the knife in the man’s hand and then you see what happened next. Cothran pulled out his Ruger pistol.

“He just said, alright, alright and backed off and made his way out the door.”

Cothran had that gun with him for a reason. In the past couple of months, there have been upwards of 15 robberies in Nashua, many targeting convenience stores like the one where he worked. He says he knew it would eventually happen.

“It was just a matter of time,” he said.

He wasn’t hurt, and even though he has a New Hampshire permit to carry his gun, he was fired for violating company policy against it. And he said he knew that could happen.

“I knew exactly what I was doing I made a conscious choice to protect my life and put myself in a situation where I would have to find new employment,” he explained. Calls to Nouria Energy in Worcester, which owns the store, were not returned Tuesday. But Cothran applauded two of his managers for trying to save his job.

While Nashua Police Lieutenant Denis Linehan wants to make sure clerks have the proper training before arming themselves, he says Cothran was within his rights.

“The clerk acted appropriately. He did fear for his life. He was in close proximity to a deadly weapon,” Linehan said.

Cothran grew up with a father and grandfather who hunted and says he has years of experience with firearms. Linehan worries, though, about those who don’t.

“As a result of them (the criminals) being in a desperate state, they’re going to do desperate things and we just don’t want to see a clerk have a gun taken from themselves and used against them. So we would just encourage anyone who is going to be in possession of a firearm that they get that necessary training,” he said.

Police hope someone recognizes the suspect in the surveillance video from inside the store, and a Coleman jacket the man took off and dropped as he ran away.

While they track him, Cothran says he’ll now look for a new job. But he has no regrets about how he lost his last one.

“I really don’t feel that I did anything this noteworthy. I just wanted to get home to my family, that’s it,” he said. “I would rather find a new job than either be in a hospital bed or in a coffin.”

Nouria Energy Corporation sent this statement to WBZ-TV Wednesday:

At Nouria Energy, our employees are our most cherished assets. Their safety and the safety of our customers is priority number one. It is with that goal in mind that we do not allow firearms in the workplace. We specifically train our employees on how to react during a robbery attempt to prevent the situation from escalating. Cashiers are instructed to give the intruder what they ask for in an attempt to resolve the conflict peacefully and as soon as possible.

Make no mistake: we care about the personal well-being of employees like Mr. Cothran, whose years of service are truly appreciated–not about the money in the cash register. So, we are especially grateful that this situation was resolved without injury.

We do respect the constitutional right to bear arms. However, we believe the best way to keep our employees and customers safe is to prohibit weapons in the workplace. Our training and policies are aligned with what is customary in the retail/conveniences store industries and is consistent with advice offered by security and police organizations.

MORE LOCAL NEWS FROM CBS BOSTON

[display-posts category=”local” wrapper=”ul” posts_per_page=”4?”]