An international disaster response expert today praised the decisions taken by rescuers at the collapsed CTV building, saying "the man on the ground is always right".
The six-storey Christchurch office block collapsed in the February 22 earthquake, claiming 115 lives.
Several survivors were pulled from the rubble by police officers, firefighters, passers-by and Urban Search and Rescue (USAR) experts.
But at least eight others who survived the initial 'pancake' collapse at 12.51pm in the magnitude-6.3 quake could not be pulled out alive from the twisted steel and concrete debris.
At an inquest into their deaths today, Ernesto Ojeda, a captain in the Los Angeles Fire Department and a 20-year USAR veteran, said the rescuers on the ground had to call on their experience and skills to make life-and-death decisions.
"The man on the ground is always right," he said.
"That person has to make the decision based on his experience and knowledge, and he has to do it now."
While he criticised senior fire managers for failing to take control of the CTV site, he was astounded by the brave actions of frontline rescuers.
They worked beneath a precarious lift shaft which was on fire, had loose debris hanging off it, and could have collapsed in an aftershock.
Captain Ojeda noted that firefighters took off their helmets to burrow into man-made tunnels to try to find survivors.
They said they left their helmets behind so if the tunnel collapsed they could be identified.
Those actions showed they were "right at the limit" of operations, he said.
"They went beyond the call of duty, that's for sure."
It was not a waste of time to remove debris by hand, he said, refuting claims made earlier in the inquest that those efforts were too slow.
Using heavy machinery could have crushed survivors trapped below, and the call had to be made on the ground.
He saw evidence of text book rescues, with voids being shored up by blocks and jacks.
USAR chiefs stood back to get an overall picture of the operation, which was "appropriate", as was splitting the large site into two separate search areas.
One of the difficulties was fighting the fire, he said, which was deep-seated, with an unknown origin and unknown cause.
Firefighters tried to "delayer" the debris to try to fight the fire, but by doing so, they gave oxygen to the fire.
They were "damned if you do, damned if you don't", said Captain Ojeda.
"This was as difficult a type of rescue you're likely to come across."
The coroner's expert witness was giving evidence at an inquest in Christchurch into the deaths of eight students at King's Education School for English Language on the concrete tower's third floor.
Dr Tamara Cvetanova of Serbia, Cheng Mai of China, Japan's Rika Hyuga, and Jessie Redouble, Emmabelle Anoba, Ezra Medalle, Reah Sumalpong and Mary Amantillo, all from the Philippines, used cellphones to alert friends, family and emergency services that they had survived the collapse, but they were not found alive.
The inquest, before Coroner Gordon Matenga, is due to conclude later today.