FORT WORTH (CBSDFW.COM) – Tense moments for patients and staff at an east Fort Worth medical clinic, after a gunman enters the building.

It happened just before the lunch hour at Texas Health Centers, near Loop 820 and Randol Mill.

Chiropractor Dr. Stacy Harris was there and told KRLD NewsRadio 1080 that the suspect was recently under medical care.

“Apparently he was sick,” she said. “He just got out of the hospital, maybe on some medications and he had a gun and we were worried that he may use it.”

The suspect, later identified Stephen Herring, allegedly went to the clinic complaining of back pain. Clinic employees said Herring pulled a gun after being taken to a patient waiting room.

“I believe he said something like, ‘How would you feel if I shot your toe?’” recalled Dr. Harris.

Fort Worth police were called to the scene and quickly evacuated the building.

The standoff began after officers became concerned that Herring was a danger to himself and others.

“He was armed, threatening to kill himself, as well as the officers on scene,” explained FWPD Sergeant Pedro Criado.

Police found the 58-year-old suspect alone and barricaded in a room.

According to officials, officers tried to negotiate with Herring but that ended with he reached for his gun.

“The officers were able to utilize a Taser, struck the individual with a Taser, took him into custody without further incident [and] were able to get the handgun,” said Sgt. Criado.

No shots were fired during the incident and no one was hurt.

Herring was taken from the scene to a local hospital and was later arrested. He has been charged with aggravated assault with a deadly weapon.