Image caption , In 2007, Spencer Beynon spoke with Hfrance.fr Wales about his experiences in Iraq
An ex-soldier shouted "I want to die " a few seconds before a police officer tasered him, an investigation found.
Platoon Sergeant Spencer Beynon, 43, of Llanelli, Carmarthenshire, has died after officers were called in June 2016 over concerns about his behavior.
He was diagnosed with post-traumatic stress disorder (PTSD) after tours in Afghanistan and Iraq.
Former CP of Dyfed-Powys, Oliver Wis, said he had "no choice " but to fire, claiming that Mr. Beynon attempted to charge.
Other witnesses, including colleague of Mr. West at the time, PC Sian Beynon, said they did not see Mr. Beynon get up until the officer discharged his gun.
Police officers responded to a report from a neighbor concerned about man walking barefoot on a road.
Officers found Mr. Beynon unconscious on the ground, "bleeding profusely " from his neck, the court heard.
Image caption, Spencer Beynon died near his home in Llanelli
Mr. West, one of the two officers who responded, told the jury he had fired his Taser wi about eight seconds after arriving, believing there was a "high level threat ".
He added: "I yelled 'hello ' twice. I walked about five to six feet away from him, then with one movement he got up.
"He screamed 'I want to die ' and then he almost rushed at me.
Mr. West said that "he " didn't know what his intentions were "and he felt he had to " defend "the people around him.
He said that Mr. Beynon took a step back and fell after being tasered, before he and PC Beynon gave her first aid.
PC Beynon previously told the inquest that she had not seen Mr. Beynon get up, but claims to have been aware of the movement, before seeing it fall.
Asked by Sophie Khan, lawyer for Mr. Beynon's family, why he failed to warn Mr. Beynon prior to dismissing, Mr. West replied: "A warning should be given unless it is inappropriate in the circumstances.
L 'Bure lawyerIndependent for Police Conduct Robert Harland asked whether Mr. Beynon's mental health was factored into his decision.
Mr. West said he was aware that Mr Beynon could be having a mental health crisis, but "the thing I was concerned about was the threat assessment ".
Police have previously denied that the Taser killed Mr. Beynon, whose family believe a welfare check should have been carried out after a 999 call .
The investigation continues.