"When you tell me that, I have had the best-case scenario. That makes me think about it again," Mr Ferkau said from his bed at the Wanaka Medical Centre yesterday.
He sustained serious lacerations to his right leg and a suspected right wrist fracture, but felt "very lucky" those were his only injuries.
Mr Ferkau, who is from Bremen in the north of Germany, said he did not have a lot of hiking or climbing experience.
He came to New Zealand 10 months ago for a year-long working holiday after completing his schooling and nine months' compulsory social service.
He and three friends, Joscha Shomaker, of Germany, Ruben Bigot, of France, and Gabriel Granback, of Sweden, arrived in Wanaka this week and intended to climb Mt Aspiring but decided against it after seeking advice from the Department of Conservation.
They heard the Cascade Saddle trek was quite nice and would give them a glacier view, so they set out on Tuesday from Aspiring Hut.
The group initially felt confident they had the right gear but knew their tent was not waterproof.
Heavy rain began falling when they reached the top of the saddle about 7pm.
"At that moment, we realised we were not not equipped for this trip," Mr Ferkau said.
They stayed overnight in the leaking tent and began their descent about 8am yesterday.
Mr Ferkau fell when he took a big step down and was toppled off balance by the weight of his backpack.
He knew there were steep bluffs to the side of the track and realised there would be little chance of surviving without injury.
"I was flying in some places."
When he stopped falling, he was shocked and tried to get up and walk.
Then the pain set in.
While he did not think he would die, he did worry about whether he would spend the rest of his life in a wheelchair.
He then realised he could move his injured leg.
His friends quickly helped him into a sleeping bag and Mr Shomaker, who has worked as an ambulance medic in Germany, talked reassuringly and held his hand while the others went to call for help.
"Ruben, Gabriel, Joscha, they did a great job. At this moment, I felt they had saved my life there," Mr Ferkau said.
He was relieved when the rescue helicopter arrived and had nothing but praise for the rescuers, who carried him through the rugged terrain to the chopper.
Wanaka LandSAR media liaison officer Phil Melchior said yesterday Mr Ferkau was lucky.
"Once you have an uncontrolled fall in that terrain, it's a lottery how you end up".
