Heta was in prison for assaulting a female in December 2016.
On the day before he died he assaulted another prisoner after voices in his head told him to. The inquest heard that Heta had ADHD and was taking olanzapine for psychosis.
Hastings Detective Sergeant Daryl Moore said he had compiled a sequence of videos from prison CCTV, which showed Heta was lowered to the ground seven times during the march, including for eight minutes while he was attended to by a nurse.
Heta's head was covered with a spit hood after he spat blood onto prison officers and the floor. Moore described the hood as made of fine mesh that allowed the wearer to see and breathe but did not allow blood or saliva to pass through. It was held in place by its own elasticity and did not have any fastenings.
Moore said the video showed Heta was offering "hard resistance" on the way. He said that the four large Corrections officers escorting him were "going down the corridor like they're drunk", because of the struggle Heta was putting up between them.
"You constantly see the struggle going on [in the video]," Moore said.
Heta finally collapsed and went into cardiac arrest about 30 metres from the at-risk unit.
Moore said his inquiry had concluded there was "no criminal liability on the part of any person or persons in relation to this unfortunate death".
Forensic pathologist Dr Kate White said the cause of death was "sudden cardiac death in the setting of restraint".
Asked if there was a causal link between the restraint and death, White said that scientific understanding was still "evolving" about how factors such as exertion, psychological stress, adrenaline rushes and medication might contribute to cardiac death.
Principal Corrections officer Perry Horua said the at-risk unit where Heta was being taken was a "safe place" where he could be de-escalated and observed.
He described the restraint and control technique used, in which four officers at a time surround a prisoner who is handcuffed behind his back. Two of the officers hold the arms and apply pressure to subdue resistance, leaning in and squeezing quite tightly, another protects the head and the fourth leads the group.
Horua said this was a "well controlled" and contained incidence of control and restraint techniques.
However, Horua said that after 26 minutes, Heta was continuing to struggle and despite officers swapping in and out, they started to lose control.
He described Heta as a "big solid lad" over 185cm tall.
At about 29 minutes, Heta lifted his feet off the ground. The team members holding him lost control and had to take him to the ground, where he was again checked by a nurse.
"There was nothing that gave me any concern for Heta at that point." Horua said.
However, after Heta was stood up and put down on the ground again, a nurse checked once more, became concerned and called for another nurse.
Heta's handcuffs were taken off and he was placed on his back. He was non-responsive and officers began CPR in relays. A defibrillator was also used before St John ambulance officers arrived.
The inquest continues.
