The rookie NYPD officer critically hurt when a hatchet-wielding stranger ambushed him and three colleagues as they posed for a photo in Queens last fall tells NBC 4 New York in his first comments since the brazen attack he thought he was going to die.

Officer Kenneth Healey, 25, and three other NYPD officers were on patrol on Jamaica Avenue in October when they stopped to let a freelance photographer take their photo. As the officers posed for the photo, a man named Zale Thompson charged them with an 18-inch hatchet, gashing Healey in the head and wounding another officer in the arm.

Two other officers shot and killed Thompson on the street, and authorities said he was still holding the hatchet when he was pronounced dead.

The attack -- and the shooting -- happened in less than 10 seconds.

Healey, who had only been on the job four months at the time of the attack, told NBC 4 New York in an exclusive interview he didn't think it was possible to get hit that hard and survive.

He said he felt something strike his head -- then there was only confusion.

“You know, one second you’re taking a picture and the next, you know, I’m staring at my skull on the floor in a puddle of blood," Healey said. "I had no idea why it happened.”

Surveillance video moments before the attack shows Thompson on a street corner crouching down to pull the hatchet out of backpack; he then charges the officers, swinging the hatchet with a two-handed grip, police said.

Healey's partner, Joseph Meeker, who was wounded in the arm, remembers seeing a shadowy figure closing in fast.

“I just put my arms up and put arms up … I remember hearing a big bang,” Meeker said. “I look over and my partner is down -- that quick.”

After striking Meeker with the hatchet, Thompson, whom authorities called a "lone wolf terrorist" who indicated he was a convert to Islam and frequented anti-American websites, headed for officer Taylor Kraft.

"I remember his beard. I remember him standing over -- and that’s when the training kicked in,” Kraft said.

Kraft and his partner, Peter Rivera, both opened fire on Thompson. A bystander was injured by a stray bullet from the officers' gunfire but survived.

“I noticed Healey was down, Meeker was down – he was chasing Kraft,” Rivera said. “We had to stop that threat.”

Once the threat had been neutralized, the officers turned to their fallen comrade Healey, who was lying critically wounded on the ground. The back of his head was shattered, part of his brain damaged.

Meeker jumped over to try to contain Healey's bleeding. Healey remembers the conversation he had with his fellow cop.

"I said, 'I am going to die. I am going to die,'" Healey recalled. "He said, 'No you are not.' He kept talking to me and kept me calm ... as calm as someone can be in that situation."

Kraft and Rivera radioed for help -– and responding officers knew there was no time to wait for an ambulance. They rushed Healey in a patrol car to a hospital – his partner still at his side.

Healey said he wanted to know the extent of his injury.

"I kept saying, 'Don’t lie to me. Don’t lie to me. I know you are lying, it's bad, it's definitely bad,'” Healey recalled.

Healey sustained a traumatic brain injury and lost 40 percent of his vision in the attack; he says he thought at one point he was paralyzed. His vision and abilities are returning, but he is still undergoing intensive rehabilitation and has not returned to work.

He plans, however, to be back on the job when he is able. He says dealing with "lone wolf terrorists" like Thompson has become part of the job as an NYPD officer.

"It's sad, but it's the world we live in right now," Healey said.

After the attack, Police Commissioner Bill Bratton said Thompson was a "self-radicalized" individual "self-directed in his activities."

In the days after the attack, a search warrant of his home computer revealed he was "visiting websites that are focused on designated terrorist groups -- al-Qaida, ISIS and al-Shabaab -- as well as looking at different acts of violence," John Miller, the NYPD's Deputy Commissioner for Intelligence and Counter-terrorism, said at a news briefing several days after the ambush.

Kraft was shaken, as was Rivera, who previously served tours in Afghanistan and Iraq while in the armed services.

“I had some close calls in Iraq, I lost one of my friends over there,” Rivera said, but added, “"Nothing as close and as personal as this.”