Finley Johnson was out on a routine patrol in the gun turret of his light armoured vehicle (LAV) when suddenly he was called to action to defend his mates.

The Nelson soldier was part of a Kiwi patrol in the northeast of Afghanistan's Bamiyan province on August 4 this year, when he was ordered to go to the aid of Afghan police and New Zealand troops whose patrol had been ambushed by Taleban insurgents.

Two New Zealand soldiers lost their lives in the battle, including his friend and flatmate Lance Corporal Pralli Durrer.

The insurgents were firing down from high rocky outcrops on either side of a long valley, pinning the troops in their place.

Trooper Johnson's vehicle led a convoy of about 12 LAVs to the attack site, just 500 metres from where he had been on regular patrol. Within minutes, his job for that day had drastically changed.

"We went to support them and ended up getting in it as well. We were right in it," he said.

"It was a narrow valley, with a river running through the middle. There were high ridges either side of the road, with rocky outcrops - the type of environment that people can hide in."

Trooper Johnson knew the situation was serious when the orders came down from command, but said it became a matter of life and death when they reached the site and he could hear machinegun fire surrounding their position.

"Being in the army you know exactly what a gun sounds like. It was no joke, no two ways about it. You know what's going on.

"We were down in a valley and really we pretty much just had to try and fight our way out of it.

"There was no running away as we couldn't turn around. We were just stuck in a firing lane, pretty much, taking bullets and taking casualties."

It was a hot day, well over 35 degrees, he said. The smell of carbon from weapon fire hovered in the air. From inside his LAV, with communications headphones on, he could clearly hear bullets raining from the hills.

Trooper Johnson's training took over as he fired a 25mm cannon from the turret control inside his LAV, using an advanced joystick and sighting system. He said it was controlled fire, following New Zealand Army strategy.

He cannot give more details about his personal involvement in the firefight, as the whole incident is under investigation by a New Zealand Army court of inquiry.

His unit was charged with recovering troops who had been hit.

He said the LAV's tie rod was damaged "amidst the chaos of taking casualties to the casualty collection point".

The firefight eased and he was outside his vehicle assessing the damage when commanders ordered the return to base.

Trooper Johnson soon realised he had lost his mate, Lance Corporal Durrer. (Lance Corporal Rory Malone was also killed and six others injured).

He had known Pralli Durrer for about two years, and had lived with him in Christchurch for eight months.

"I would say to describe Pralli, he said what he thought and he wouldn't let anyone tell him any different. He wasn't a big man, but he certainly had the heart of a lion.

"I am just really glad to have known him for the time that I did - we got pretty close."

After the fatal ambush, the atmosphere was "shellshocked - literally" at the Kiwi base.

"When we found out [about Pralli's death] all the boys were pretty cut up, especially those that knew him a bit closer." Everyone was "more tense, more wary" around the camp after seeing their mates killed.

Finley Johnson will forever wear the memory of that fateful August firefight, in ink on the inside of his left arm.

Days after returning home to Nelson he got a tattoo based on the design of one his fallen mate had. It just reads "Pralli D"..

- © Fairfax NZ News