"There's someone hurt here and he's dying right there, lying in all the dirt with his body smashed to smithereens. But he's still talking. I'm so proud of my boy," she said.
"He stayed awake the whole time with his horrific injuries. His boys [colleagues] were around him. It was raining. It was getting cold. They were all waiting for the helicopter. They were all waiting for the doctor."
Ms Hikairo said her son was still conscious when he arrived at hospital and went into surgery, but by the time she arrived from the Coromandel he was no longer awake as an infection spread through his body.
He was in intensive care but died on Good Friday morning, she said.
In hindsight, she wished her son hadn't been rushed straight to surgery and instead was made comfortable and able to spend his last hours with his family.
An ambulance arrived on the scene about 40 minutes after Mr Maungarongo was struck but St John Far North territory manager Ben Lockie told the Northern Advocate the injured man then needed to be carried up a steep 120 metre bank.
He said the task was "very difficult" and there was an initial reluctance to move Mr Maungarongo because of the severity of his injuries.
The Northland Rescue Helicopter was called too, but couldn't land because of bad weather.
"Unfortunately [in Northland] there's a huge reliance on helicopters and they're just too much of a risk when the weather is really bad. It was a very unfortunate situation," Mr Lockie told the Advocate.
Ms Hikairo said the timing of her son's death was doubly tragic as he was looking forward to his two oldest children visiting at Easter, the first time he'd seen them in four years.
He was farewelled at a tangi at Te Keeti Marae in Otorohanga on Saturday.
Mr Tai went to high school at Hato Petera College in Auckland.
"He could have chosen to do anything but he chose to be a bush rat," his mother said.
After working in forestry around the country, he ended up in Whangarei, where he made friends, was in a relationship and took up boxing. He was making a name for himself under his ring name of "Mau"
He had a softer side too. He liked to make home movies, and write songs and poetry, Ms Hikairo said.
His mates at the Whangarei Boxing Gym are having their own memorial tomorrow night - a BBQ and a few beers.
Mr Tai was a heavyweight and had won all three of his corporate fights. Next step was making a name for himself in the amateur ranks.
"I thought he was very tough. He was a big boy, tough as an ox. He was a good fighter and a really good bloke" said Tim Bowman, from the gym. "He was a close mate of mine too."
WorkSafe NZ is investigating and Mr Tai's death has been referred to the coroner.
