As Dr Munjed Al Muderis landed in Baghdad, he suddenly questioned whether he had made the right decision to return.
"I had this chill feeling," he told the ABC.
"What have I done? I am back to the place I escaped from."
Eighteen years ago, the acclaimed orthopaedic surgeon escaped the brutality of Saddam Hussein's regime.
He was forced to flee his homeland of Iraq in 1999 after he refused to cut off the ears of army deserters as a young trainee doctor in a Baghdad hospital.
"The head of the department refused openly, and they took him outside to the carpark, and they put a bullet in his head," the doctor recalled.
"I was confronted with a decision. Would I obey the commands and live with guilt for the rest of my life?
"Would I refuse and end up with a bullet in my head, or would I run away?"
The young doctor came to Australia by boat, spending 10 months in immigration detention which he describes as "hell on Earth".
"I was stripped of my human identity. We were locked behind barbed wires," he says of the now closed Curtin detention centre in remote Western Australia.
Because he could speak good English, he would stand up for other detainees if he felt they were being treated unfairly. As a result he was labelled as a troublemaker and often punished for being outspoken.
"I was marked with a permanent marker on my shoulder with a number, 982. I was put in solitary confinement," he said.
"No matter what I say about it, I would not give it justice."
Two months after being released from Curtin detention centre, Dr Al Muderis qualified as a doctor to practise medicine in Australia, and received his first pay cheque.
10 days of life changing surgery
Today, after years of hard work rebuilding his life in Australia, he is one of the country's foremost orthopaedic surgeons.
But Dr Al Muderis' new life was suddenly interrupted earlier this year when he received a call from the Iraqi Prime Minister's office.
They had read about the pioneering work he has been doing in "osseointegration" — a relatively new type of surgery helping amputees walk again using robotic implants.
The Prime Minister asked if he would consider coming back to his homeland and helping out.
"Iraq has one of the largest number of amputees and disabled people due to the wars Iraq went through and is going through," the doctor explained.
"I said yes, I'd be more than happy to help."
The Sydney-based surgeon assembled a group of volunteer staff to travel to Baghdad and assist him there.
The ABC accompanied the team to record the highs and lows as they worked around the clock, performing 10 days of life-changing surgery.
Ali Bassam, a 29-year-old former soldier, was one of the first patients to be treated.
"We were surrounded by ISIS. We had used nearly all our bullets and grenades," the young father told the ABC.
"I was injured when they attacked us with suicide car bombs."
When Mr Bassam lost his leg, his wife walked out on him, worried he would not be able to provide for the family.
He was left to raise their young son Hussein alone.
Patients hope for a second chance at normal life
Now thanks to Dr Al Muderis, Mr Bassam has the chance to get his mobility back, becoming the first person in Iraq to receive the osseointegration implant surgery.
"They called me and told me we can do the implant surgery so you can have the new leg!" Mr Bassam said happily.
"I was just so happy, thank God."
Ghadban, 22, lost both of his legs earlier this year when he was walking to college in Mosul and a mortar hit him.
"I told them I want to die and not to have my legs taken off," the young student said.
Desperate to walk again, Ghadban found out about Dr Al Muderis' work after trawling the internet and seeing videos of amputees walking with their new legs.
"I thought 'here is a person who will make me walk as best as possible'," Ghadban recalled, smiling.
"He is pretty much the best in the world. The walk is normal. I was very happy.
"That night I was so happy I couldn't sleep."
The young student dreams that if the surgery goes ahead, he may have the chance to try and live a normal life.
"I am in love with a girl," Ghadban said softly.
"I was going to propose to her after we got rid of ISIS. But when I was injured, her mum said to her this can't happen. That man is crippled.
"My girlfriend said to me if you started walking … maybe then my mum would agree.
"I am trying to do the operation to walk normally again. I will propose to her then."
Confronting the toll of war first-hand
Over the course of their visit, Dr Al Muderis and his staff performed dozens of surgeries trying to help as many patients, such as Ali and Ghadban, as they can, before returning home to Australia.
The trip is an emotional and eye-opening experience for Dr Munjed, as he confronted first-hand the terrible toll that years of war and fighting have taken on Iraq.
"I couldn't stop hiding my shock to the severity and the complexity of the injuries these people have and unanimously, every single member of my team, the minute they look at an image they say 'oh my God, what are we going do with this?'" says Dr Al Muderis.
"I can't claim that I'm a machine. I try to be non-emotional, and I try to separate feelings from my work, and then try to be as pragmatic as possible, sometimes it does get into you.
"Seeing the number of people that are desperate. But what you do? Just try to do as much as I can."
Just a few days ago, the ABC was invited to travel back to Iraq with Dr Al Muderis, as he continues to see patients and train teams of Iraqi doctors and medical staff to do this type of surgery and continue the work without him.
It's time to see if the surgery he performed on Mr Bassam and Ghadban has worked and whether or not it will allow them to live any kind of normal life.
It's a particularly rewarding part of the process for Dr Al Muderis to watch patients who were previously confined to wheel chairs for the most part, because of how difficult it can be to walk any distance in old fashioned prostheses, finally take the first few steps into their future.
Watch Foreign Correspondent's Machine Man tonight on ABC TV, 8:30pm.