Mr Rundle had been cleaning out his garden shed on Auckland Anniversary Day when he slipped and plunged down the cliff at the back of his property, which overlooks Castor Bay.
"I've done a lot of rock climbing and abseiling so I know you must always know at any time what you're going to do if things go to custard, what your plan is.
"My plan was to spreadeagle face down and control my descent as much as I could.
"I knew that I was increasing in momentum and I was increasing the possibility of a serious or fatal injury ... I was grabbing on to things to stop me from rolling - because if I started rolling I would have lost control completely."
As he landed his left arm became wedged between rocks.
"I got a fair crunching on those rocks on the way down ... I was lying with waves splashing around me. I thought 'what next? What's the tide? How high is it? Which way is it going? Am I going to survive this? Am I going to drown?'
"I didn't want to drown after getting down there alive. I worked out that I could manage, I could keep my head up so I could breathe if the water level rose. Then, I had to turn very quickly to the three Bs - breathing, beating, bleeding.
"The bleeding was the worst. 'What do I do if I find I'm gushing from somewhere,' I thought to myself. I decided I would used handfuls of sand to stem any heavy bleeding."
He had a gash to his head but it was "only trickling" and he knew he had broken a few ribs, but otherwise, his biggest problem was his trapped arm.
"Then I decided 'right, it's time to get out of here'. I tried the quick way first - calling for help. I got no response, which wasn't surprising because of the noise of the high tide. Then I remembered I was carrying my cellphone."
Mr Rundle's wife Pauline, who had returned home from a quick trip to the shops to find her husband missing, was calling his phone repeatedly.
"I kept saying, 'Stop ringing me, you're running the battery down and I will need it soon,'" he said.
To get his phone Mr Rundle had to manoeuvre himself out of his shorts.
He then passed out. He would be unconscious for several hours - all the while his wife was frantically searching for him. Luckily, the tide did not get higher.
"I woke up eventually and I resumed the plan. I was a bit like Houdini," he said.
He inched and twisted the shorts down his leg until he could reach his cellphone and call 111.
Emergency services descended on Castor Bay and Mr Rundle was rescued.
"I was anxious that I was not going to make it. I was thinking, 'I'm either going to drown before I am saved, I'm going to bleed to death before I get found.'"
Mr Rundle slipped in and out of consciousness and does not remember much of being winched into the Auckland Westpac Rescue Helicopter or being rushed to Auckland City Hospital.
He suffered a badly broken left shoulder and possible nerve damage on his left side, three broken vertebrae in his neck and two in his back, multiple breaks to at least six ribs, a punctured lung and was grazed and gashed all over.
"The first few days were rugged, but made immensely less so by the wonderful staff and care this hospital provides," he said.
He will remain in hospital until his vertebrae heal.
"I'm just taking it a day at a time at the moment. I feel very, very lucky."
He thanked police, Fire Service, St John and helicopter staff that came to his rescue.
"They saved my life."