A customer at an Arby's wrestled a gun away from a prison inmate Monday, about an hour after the escapee used it to kill a corrections officer during a medical appointment, authorities said.

Curtis Allgier, whose heavily tattooed face has a swastika and the words "skin head," was unarmed when he was captured inside the fast-food restaurant.

"It sounds like he was heroic, even though he's being humble about it," Salt Lake City police Sgt. Rich Brede said of the 59-year-old man, who didn't want to be identified.

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Utah corrections officer Stephen Anderson was shot in the head while alone with Allgier in a room at the University of Utah orthopaedic center.

Allgier, 27, was there for an MRI because of lower back pain and somehow got Anderson's gun, said Tom Patterson, director of the Utah Department of Corrections.

For an MRI, a prisoner's metal restraints at the wrists and ankles typically are replaced with a plastic "flex cuff" to avoid problems with the procedure, Patterson said.

"We do not know exactly what happened" in the room, he said.

Anderson, 60, of Bluffdale was a 22-year department employee.

"This is one of the risks in the job we perform for the community," Patterson said. "Unfortunately the risk sometimes is our very lives."

Allgier fled the clinic on foot, carjacked a Ford Explorer and led police on a 100 mph chase on city streets and Interstates 15 and 215.

He drove the SUV across tire spikes on I-215 but still was able to drive several more miles before bailing out in the Arby's drive-thru lane and running inside the restaurant.

Allgier fired one shot at the Arby's but no one was hit. A customer was able to snatch the gun from him, possibly preventing more bloodshed, Brede said.

"There's no telling what the suspect would have done," the sergeant said.

Allgier was captured while hiding in an office and later transported to the Salt Lake County jail to await charges.

With two hospitals as well as specialty clinics, the University of Utah is a major provider of health care in the region and regularly sees inmates from the state prison system.

"Typically, the Department of Corrections provides the level of security they deem necessary," campus Police Chief Scott Folsom said. "It is not usually the case that they call us to tell us an inmate is coming because it's such a routine occurrence."

Allgier was in prison on a parole violation. His criminal record includes burglary, forgery and at least one weapons crime, according to records.

While Allgier was on the run, he called a friend, Trisha Tower, to say he had shot an officer and was sorry.

"I didn't even know how to deal with that," she said in an interview at her Salt Lake City home.

"Nobody knows what happened in that room between the two of them. ... I feel sorry for that family, but I have a loss, too," Tower said.