He believed officer 12 had made a crucial mistake by driving so close, endangering his and officer 12's life.
Officer 11 said Mr Kelly-Tumarae left his vehicle, with the shotgun in one hand and an ammo belt around his shoulders, stared and smiled at him with a "big grin" before raising the gun.
"It made me think I was about to be shot. I thought I was going to die then and there."
He said something distracted the teenager which likely "saved my life".
"The next thing I heard was shouting and shots."
Officer 11 said as Mr Kelly-Tumarae was being cuffed and arrested by fellow officers the 19-year-old was yelling "f..k the police" while lying in a "pool of blood".
Earlier, the police officer who fired 14 shots told the inquest he believed he and his fellow officers would die in a barrage of gun fire, a coroner's court has heard.
Officer six said he saw Mr Kelly-Tumarae exit the vehicle and aim the shotgun at two police officers, looking like a "Mexican bandoleer".
"He looked like he meant business and wanted to kill whoever was in the vehicle," officer six said.
"I'm going to see brains coming out the other side of the vehicle."
Officer six stepped out of the car and shouted "armed police" before Mr Kelly-Tumarae turned to face him.
"The barrel was pointed in my direction and I thought he was going to shoot me. I thought I was going to wear it."
The officer then, believing he was about to be attacked, fired "four to five" rounds in quick succession at Mr Kelly-Tumarae.
"I thought, 'He's still standing and still facing me. I haven't hit him'."
The officer then fired another five or so shots before Mr Kelly-Tumarae ran towards the cemetery before dropping the gun and collapsing.
"I wanted to dominate him, I wanted to be aggressive and wanted to go home at night."
After walking towards Mr Kelly-Tumarae he said the teenager looked "white as a sheet" and "dead".
Officer six said: "I wish this had never happened, I wish he had pulled over somewhere else. I wish a lot of things.
"There's not a day that goes by that I don't think about it.
"I don't regret my actions as a police officer... I took an oath and my job was to protect those two officers.''
Mr Kelly-Tumarae's grandmother, Narina Tumarae, yesterday gave the court an insight into the behaviour of her grandson the night he was killed.
"He had a nice smile on his face - all he said was, 'You alright nan, what are you doing'."
She believed her grandson went to bed after returning home and was unaware, until informed by police, he had left the house and taken off with her late husband's shotgun, ammunition and her car.
"I've been trying to run it through my head, why? I've never seen him touch that gun or use that gun before."
Last year the Independent Police Conduct Authority released its 94-page report into the early-morning shooting at Omahu.
The report found a Hawkes Bay policeman's 14-shot volley, which killed Mr Kelly-Tumarae, was justified because of the threats to the officer's own safety.
Investigations revealed the officer fired 14 shots, four wounding the teenager and another appearing to have passed through Mr Kelly-Tumarae's clothing without causing injury. The other nine bullets did not appear to have hit him or his clothing.
Coroner Peter Ryan said: "I am not in a position to make my findings today."
He said it will be some weeks before he presents his written findings on the inquest.
