The incident in January is one of many dramatic rescues featured in the new series of TV2 reality show Code:1.
Intensive care flight paramedic Rob Gemmell said it would have been touch and go if the on-board doctor had not inserted a chest drain to relieve pressure on Mr Mullinder's lungs.
"The patient's chest had been crushed and I pumped him with pain-relief drugs while the doctor cut a hole in his side."
Pump technician Mr Mullinder, also a volunteer firefighter, was then airlifted to Whangarei Hospital.
"The accident happened on my 12th wedding anniversary," he said. "Before I set off ... I told my wife, Nyree, I wouldn't give her a big smoochy kiss until I got back, because we had not been married until 4pm. Needless to say, I didn't make it back that day and I still owe her a proper anniversary dinner."
The rescue is one of more than 600 so far this year by the Auckland Rescue Helicopter Trust - 35 per cent more than at the same time last year. Each mission costs an average of $5000.
Code:1 is at 8pm Thursdays on TV2.