He stated that pulling the first officer out of the cell would have increased the risk of harm to those involved.
"I take a lot of pride in my decision-making and if I could go back I'd do the same thing. I still think even in hindsight I made the correct decision," he said.
But authority chairman Judge Colin Doherty deemed that the officer's use of pepper spray was unnecessary and was "an excessive use of force".
"The officer was focused on subduing the man with the use of pepper spray, which came at the expense of good, sound, decision-making in accordance with Police policy and best practice," he said.
The authority reported that a lower level of force should have been applied before resorting to the use of pepper spray - some staff witnesses to the incident agreed.
Other staff members supported the second officer for using pepper spray on the basis that his actioned enabled officers to exit the cell safely without having to engage physically.