"I take a knife and I slash you open, take something out, put it back together and walk away as if nothing happened."
It's a wonderfully succinct way of putting a job title that includes operating on Presidents, Supreme Court judges and the rich and famous of New York.
It's a long way from Sir Murray Brennan's Onehunga roots, and it's one of the few times the acclaimed surgeon looks at things in such a simple, black and white way.
The university years
It was 1963 and in the midst of the Vietnam War, and a 23-year-old University of Otago graduate named Murray Brennan had just won a Foreign Leaders Award, an award handed out by the US State Department to 13 students around the Pacific Rim.
They would travel across the US and put on debates at universities around the Vietnam War.
"We had a little green matchbox and a little red matchbox, and five minutes before you went on stage you pulled a card," Sir Murray told Newshub.
"So one day I was telling you the Vietnam War was the greatest thing that ever happened, and the next night I was saying, 'What do you mean, you think you're going to impose democracy?'"
And so Sir Murray and the 12 other students would travel around the country forming arguments both for and against the war each night.
People back in New Zealand were eager to hear about his experience and what he'd learnt.
"What do you think of the Vietnam War?" They'd ask.
"Well, which side do you want me to be on?"
"No, no, we want to know what you think."
But Sir Murray couldn't answer that.
"I realised I didn't know what I thought. That was a major event in my head. I could argue for and against and I didn't actually know what I thought.
"So from a pretty early age I realised I could make the argument for both sides, but the real question was, can I do the homework to find out what the truth actually is?
"Finding the truth is very difficult, and I became very adverse to people who saw everything as black and white - there's far more grey than black and white."
His analytics would hold him in good stead as his open mind and ability to look at things from all sides saw his fledgling medical career begin to take flight.
Chairing Memorial Sloan Kettering
"I didn't want to be a chairman," said Sir Murray, before detailing his 21-year span as chairman of the surgery department of the world's most prestigious cancer hospital.
"You take jobs for two reasons: you either want them, or you don't want someone else to have them."
It was the latter which spurred Sir Murray to take the job as chairman of Memorial Sloan Kettering's (MSK)surgery department in 1985, a position he would not relinquish until 2006. The position allowed Sir Murray to maintain his operational schedule despite his leadership duties, a role he gained a great deal of satisfaction from.
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"The people that we train [at MSK] have finished medical school, done five years of surgery, at least two years of research, and then we get two years to mature them.
"That's an unbelievable gift, because you've got people that to get here are super smart, way smarter than me, but they don't know that at the time.
"I've loved operating on the rich and famous, but the real jewel has been the young people that I've influenced."
His acknowledgement that the young doctors were often smarter than him helped to form the foundation of his leadership values. He encouraged them to analyse things from both sides - be prepared to accept the truth may be grey - and challenge them to challenge him.
"You can say anything you want to me politely," is one of the first messages Sir Murray gives young doctors.
But a culture of freedom of expression is desirable in theory but difficult to truly create.
"It wasn't easy. When I came here, I had senior people who thought they knew everything. They would tell me that I shouldn't try and learn anything, and if I just stayed [at MSK] long enough I'd learn it."
"That was a culture I had to break."
He did it by hiring young, open minded thinkers and ingraining the culture of freedom of expression early in their careers.
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Was it successful? Sir Murray believes so, and in his 21 years he has overseen the maturation of more than 300 surgical oncologists, according to a report in the ASCO Post. Many of those have moved on to leadership positions at hospitals in the US and around the world.
MSK was and remains the world's premier cancer surgery hospital, and Sir Murray boasts an impressive, though mostly confidential, client list.
Justice Ruth Bader Ginsburg, the noted associate justice of the US Supreme Court who made public her surgery for pancreatic cancer in 1999, is among them.
The culture dismantles
In 2006, Sir Murray stepped down as chairman of the surgery department after a 21-year stint.
He's remained heavily involved with the hospital since, but admits the difficulty with which he's had to sit by and see an erosion in the hospital's culture, largely - according to Sir Murray - through a lack of transparency among senior figures.
It culminated in a New York Times report last month that saw the hospital's chief medical officer, Dr Jose Baselga, resign after he failed to disclose extensive industry ties - including receiving payments from companies connected to cancer research.
Further, a report from ProPublica in conjunction with the Times, revealed MSK CEO Craig B Thompson would resign his seats on the board of pharmaceutical company Merck, an extension to the fallout over cancer centre leaders and for-profit pharmaceutical companies.
"The culture that we built was being dismantled," Sir Murray said.
"That's why this happened, it wasn't a one-off event. There's no question that this behaviour was unacceptable, and it was less so the behaviour than it was the failure of transparency.
"Unacceptable behaviour became acceptable, mainly through the lack of transparency.[Now] the most famous cancer hospital in the world is suddenly looking pretty bloody awful."
Sir Murray was asked by senior figures at the hospital, including the president, why he didn't interfere.
"I was not the chairman anymore - my job is to support [the new regime], and if I don't agree with you then I should just step back.
"I agonised over that, but all I could do was continue to be who I am, and to encourage the young people to behave appropriately.
"The good news is the young people have not yet been contaminated - the people who I talk to, they still have aspirations to do a better job."
Sir Murray believes the culture problem is symptomatic of problems reflected across the health industry in the United States.
"The medical system is broken. And the tragedy is there's no good guys in this. The patient has unrealistic expectations, the doctor is encouraged to over-investigate and to some degree over-treat, the insurance company only wants to insure healthy people, the drug company wants to invent drugs that cost staggering amounts of money.
"There's not a single good player."
Sir Murray hopes this crisis will herald a turn in culture for the good.
"It'll be key. A lot of things have to change, and I'm hopeful that I can impact on them. You have to acknowledge that the culture needs to be changed, and I believe the current CEO and board chairman are aware of that."
At 78, Sir Murray is well aware he is in the twilight of his career, yet he remains active.
He still works at the Memorial Sloan Kettering hospital on Manhattan's Upper East Side, where he's the vice president for international programs, chairman emeritus of surgery and Benno C Schmidt chair in clinical oncology. He also works as an extremely part-time tractor driver on his son's vineyard in central Otago.
When asked when he might pack it all in and take a proper retirement, he estimates two years, but for this self-confessed workaholic you get the impression it won't be quite so black and white.