"I looked up and I can see the dust, wind or something, and then I can see something like a rumbling sound and it started to collapse," he told media from his hospital bed on Monday.
"I could see the big part of the cliff, parting and start to slide down and I thought 'oh shit' it's really collapsing."
Son grabbed his friend's hand and rushed towards the sea. The skiier with experience of avalanches decided it was the only way to get further from the collapse.
"The rumbling sound got louder and louder. Then my friend tumbled. I tried to reach my friend. I almost reached my friend, almost covered my friend, I could place myself a little bit behind her.
"I thought a little bit like I couldn't make it. I was hit by rocks, kept getting hit by rocks. As soon as it was done I tried to get to the surface, I tried to find my friend," he said.
"Maybe a second later, my friend popped up through the surface. It was really lucky we could both swim and we were not covered by rocks."
The incident sparked a mass emergency call-out. Numerous helicopters, ambulance and fire engines, as well as people on the beach, helped with the rescue the pair.
Orthopaedic surgeon, James Blackett treated the pair at Hawke's Bay Hospital.
Son underwent several surgeries - the his fibia was broken and his tibia had broken into three parts.
His friend sustained a pelvic fracture and a femur (thighbone) fracture. While the latter fracture will heal, it is the broken pelvis which needs to heal on its own, Blackett said.
"These kinds of injuries take a year or two to start to get back to the kind of function you had before."
Originally from South Korea, the pair have been in the country since January 2018, on a working holiday visa.
Just a few days prior to the accident, they had renewed their visas for three more months. Now, all they want to do is return home.
"I didn't plan to spend my visa in this way."
Son says the main reason he has spoken publically is to thank those who helped him.
"I really want to say thank you to all the people who helped us. Emergency staff, or people, tourist and citizens or whoever helped us. We were really lucky that we could have people around us at the time."
Since the incident, access to Cape Kidnappers has remained closed, while specialist engineers assess the risk.
A Hastings District Council spokeswoman said it would not make any decisions on whether or not to re-open access from Clifton Beach until it receives the geologist's report, which will include potential risks in the area.
In the meantime, public safety remained a priority, and people were instructed to stay away from this area until further notice.