Gun in the workplace saves woman's life, after attacker beheaded a woman, he was shot while he was stabbing another woman

In this case, the shooter was a reserve deputy, but it is still a case where they were very happy that there was a gun in the workplace.  From KFOR.com about the attack in Moore, Oklahoma:

Officials with the Moore Police Department say the FBI is now involved in the investigation related to a brutal attack of workers at a food distribution plant.
Sgt. Jeremy Lewis says the alleged suspect, 30-year-old Alton Nolen had just been fired when he drove to the front of the business, hit a vehicle and walked inside.
He walked into the front office area where he met 54-year-old Colleen Hufford and began attacking her with a knife.
Sgt. Lewis confirms the type of knife used in the attack is the same kind used at the plant.
Lewis confirms that Hufford was stabbed several times and that Nolen “severed her head.”
At that point, Lewis claims Nolen met 43-year-old Traci Johnson and began attacking her with the same knife.
Officials say at that point, Mark Vaughan, an Oklahoma County reserve deputy and a former CEO of the business, shot him as he was actively stabbing Johnson.
“He’s, obviously, a hero in this situation,” Sgt. Lewis said, referring to Vaughan. “It could have gotten a lot worse.” . . .

CORRECTION: Vaughan is a concealed handgun permit holder and he is a current, not former, executive at the company.