This is JUST LIKE the Fairchild Air Base Mass murderer.
Air Force SP Andrew Brown stopped that rampage with a long range pistol shot from his M-9. Davis was armed with a Mak-90 w/75 round mag. A remarkable fete of arms.
On 20 June 1994 a mass murder occurred at the Fairchild Air Force Base, Hospital near Spokane Washington. Dean Allen Mellberg, the killer, had mental health issues since birth. He joined the US Air Force in 1992.

During basic training his Military Training Instructor referred him to the Mental Health facility where it was determined he was not military material. The Commander of the Basic Training squadron disregarded the Mental Health professionals and the Training Instructor’s recommendations. She kept Mellberg in the Air Force. This was the first of many missed opportunities that permitted the seeds of psychopathy to germinate.

Mellberg graduated basic training and went on to Lowry AFB in Colorado, where he learned his trade as an equipment calibration specialist. The school was long, and he went through several roommates, all of them complained of odd behavior. He threatened to kill one of his roommates. He was often seen sitting by himself laughing out loud. At other times he quietly stared at the walls. His instructors at Lowry AFB referred him to Mental Health who again recommended discharge. School officials overruled the instructors and the medical staff, keeping Mellberg in the school and in the Air Force because he made good grades.

In April 1993 Mellberg graduated tech school and reported to his first duty station, Fairchild AFB, Washington. He was assigned to the 92nd Maintenance Squadron and shared a room with another new Airman from the same Squadron. His roommate found him to be oddly quiet, and difficult to get to know. When he asked him where he was from Mellberg said, “I need to get to know people better before I answer questions like that.” That was just the beginning; Mellberg started masturbating in front of his roommate and his girlfriend. When he refused to stop this behavior the roommate went to their First Sergeant for help. Mellberg was referred to Fairchild's base Psychologist and Psychiatrist. They immediately saw trouble in Mellberg and recommended to the Maintenance Squadron Commander that he be discharged.
The Commander wanted to give Mellberg a chance to earn the money the Air Force had just spent training him so he ignored the warnings and let Mellberg stay in the Air Force, after all he was doing “ok” at work.
Mellberg obsessed about the complaint being in his permanent record calling it a crime against humanity.
Fairchild's Mental Health doctors sent Mellberg to the in-patient psych ward at Wilford Hall Medical Center, Lackland AFB, in Texas. Over a period of three months he was diagnosed with several disqualifying mental health issues. Mellberg again avoided discharge and was assigned to Cannon AFB, New Mexico.
After four months at Cannon Mellberg was discharged for a personality disorder. It happened so fast he did not have time to fight it. He refused a plane ticket home, instead opting for the cash value. He withdrew his savings of $6000 and eventually ended up back in Spokane Washington.
He bought a MAK-90 rifle and a 75 round drum magazine. On the afternoon of June 20th, he took a cab to the base Hospital arriving just before 3:00 pm. Mellberg entered the Hospital with his rifle seeking the two doctors who he blamed for his discharge and the ruination of his career.

In a few minutes he had killed five and wounded twenty-two.
Those who were not physically wounded have long suffered the scars of mental trauma.

--
Of the Troops & For the Troops

...said that he had received a General Discharge.