Mr Buck was speaking on the sixth day of prosecution evidence in a trial in which four Hawke's Bay police officers have denied separate charges of assaulting Mr McPeake with a weapon.
A jury has been told nothing any officer did contributed to the death of a 179kg man who had a heart condition, had taken an array of lethal drugs and was believed to have been suicidal.
Mr McPeake, 53, had been wanted for several hours after attacking his 76-year-old father at his parents' Hastings home.
The arrest was launched when an officer found his vehicle in a beach carpark at 12.49am.
Mr Buck, who had also reviewed the statements of seven officers at the scene, said the plan for the arrest was a good one, but appeared to have no contingency if Mr McPeake were to refuse to comply with requests or resisted the offices.
Up to the point the windows were broken, Mr McPeake was showing passive resistance, Mr Buck believed.
But he said there was "nothing more than active resistance at best" thereafter, rather than being "assaultative".
Mr McPeake's actions included shutting the driver's door after it was opened by an officer, and clasping the muzzle of one of the dogs.
He told Crown prosecutor Ben Vanderkolk that if it were thought Mr McPeake could be armed with a crossbow, as some of the officers feared, an "assault" on the vehicle was not the "appropriate tactic".
Other options included cordon and containment, more voice appeals, and possible introduction of the armed offender squad, which was not used on the night.
It had been said the advance on the vehicle followed the activation of the vehicle's windscreen wipers during the voice appeals.
Some took the wipers as an indication Mr McPeake may have been about to try to drive off.
Mr Buck said there was a 4 to 7 minute gap before the assault on the vehicle started, indicating it had not been a spontaneous decision.
But, once the decision was made to break the windows, the option of using spray was a good one, he said.
(Proceeding)
