"If it had been available, I would have acquitted you on that charge also."
The maximum penalty for arson is 14 years in prison, but Justice Heath chose a 12 month home detention sentence over sending Taiaroa back to jail, because he thought it was in his best interest and the best interest of society.
"You are plainly in need of medical care for mental health problems and are unlikely to have an adequate opportunity to integrate into the community were you to return to jail," the judge said.
"I'm satisfied that your safety would be at risk in jail, inparticular retribution as a result of your efforts to extract yourself from the gang."
Home detention reflected the seriousness of the crime, and would allow Taiaroa better access to counselling and other self-help courses.
However, Justice Heath had a warning for Taiaroa, saying it was likely his last chance to ditch his life of crime.
"I have the sense that you have finally understood the need to turn you life around and leave behind your criminal links of the past," he said.
"I hope that with the assistance of [his doctor] and a probation officer you can achieve that goal.
"This is likely to be your last chance to do so. I wish you well."
During his defence, Taiaroa claimed he was forced to participate in the June 2013 riot at the north Waikato corrections facility under threat from other prisoners.
Taiaroa was captured on CCTV footage picking up toilet rolls and carrying them towards another prisoner who was in the process of fuelling the main fire.
He was also spotted with a small group of inmates using a metal volleyball pole as a "battering ram" against a staff base window, and at various pointes striking the window and surrounding walls with lengths of wood and a metal object.
"I am satisfied that Mr Taiaroa believed that, if he were not to participate in the riot, some of those prisoners would (colloquially, speaking) 'give him the bash'," Justice Paul Heath said in his written judgement when issuing his guilty verdict.
"I find that he harboured a genuine belief that threats of immediate grievous bodily harm were being made against him and would be carried out."
The mass brawl at unit 16B was one of the worst in New Zealand history, and saw prisoners smash windows and furniture to pieces and fashion them into weapons to cause further damage. A group of inmates broke into the guard room and attacked an officer with a metal volleyball pole. A number of fires were started in the prison, including a huge blaze in the middle of the compound.
It was sparked by the discovery of two containers of 'homebrew' by prison staff.
The cost of the eight-hour rampage topped $10 million.
More than 20 prisoners were charged with serious offences in relation to the riot.