An inquest was told that skiers had been assessed on their skill that morning, with Mr Choi deemed an intermediate, or level two.
The instructor, who was responsible for supervising eight people, allowed the urologist to join his more advanced group after Mr Choi requested to be moved up, so he could ski faster.
Mr Drigo agreed and said the doctor had “underestimated” his own ability, and should therefore join the “level threes”.
Later that day, the instructor’s ski group ventured off-piste to the Losset corridor, which was where Mr Choi lost his skis and suffered the fatal fall.
The father of two also lost his helmet on impact when his head struck a “banana shaped” rock, before he continued rolling down the hill, the inquest heard.
Despite efforts to revive Mr Choi after his fall, he died a short time later having suffered traumatic neck and spinal injuries.
‘Everything was very fast’
Eyewitnesses recalled how Mr Choi had “listened and followed instructions” given by Mr Drigo after reaching the top.
However, his skis had caught an outcrop while he was travelling down the 35 degree slope, which caused him to tumble.
By the time he stopped at the bottom of the corridor, he had fallen more than 750ft.
The inquest at Archbishop’s Palace, in Maidstone, heard that the instructor was convicted of involuntary manslaughter by French prosecutors.
Mr Drigo denied taking drugs or alcohol when questioned by French police, but he was later found to be under the influence of cannabis.
This may have impacted his judgement, the inquest heard.
During questioning, Mr Drigo said: “When William fell I could not do anything to avoid his fall, because everything was very fast.”
Investigators had found the snow was hard and icy, which made it difficult to ski, despite the instructor claiming it was “powdery”.
Patrols from the resort, who were called to help an unconscious Mr Choi, later pointed out to police the difficulty that these conditions pose.
While the Losset corridor is not considered extreme, it is nevertheless reserved for “experienced skiers” and “many falls” had taken place on the slope that morning, the inquest heard.
‘Accident could have been avoided’
A post-mortem examination found Mr Choi had died from neck and spinal injuries known as craniocervical and thoracic trauma.
Sonia Hayes, assistant coroner, said the surgeon had been on the verge of progressing from level two to three, but had an “inadequate introduction to off-piste skiing”.
A toxicology report found no drugs or alcohol in Mr Choi’s system which could have impacted his senses or judgement. There were also no defects with his equipment.
A couple, Helen and Roger Hughes, said they had quit Mr Drigo’s group before the incident because they felt it was “too extreme” for them.
Mrs Hughes said: “In my opinion, the accident could have been avoided if the ski instructor had correctly assessed their ability.
“Philippe never asked if we were okay and if we were happy to carry on. As such, I decided to leave the group and decided the site he was taking us on was too dangerous.”
The assistant coroner concluded: “I am satisfied it would not be sufficient to say that it was simply an accident. We have heard from Mrs Hughes that this accident was avoidable.
“I am satisfied that on the expert evidence given to the French public prosecutor, they held a manslaughter charge in this case.”
She agreed with the French courts that Mr Choi’s death was caused by gross negligence, but it was not revealed what penalty Mr Drigo faced.
Speaking after the accident in 2016, Mr Choi’s partner said he was a “very experienced skier” who “always wore a helmet and didn’t take risks”.
He was a highly respected consultant and the lead urology surgeon for renal cancer in the East Kent Hospitals Trust.