In her debut mission, in Syria, she mostly performed war surgery on people with gunshot injuries.

"You're never really prepared for how bad the surgery is," she says, "and I certainly felt that I was a little unprepared as a surgeon, technically, for some of the things presented to me.

"Because the war was going on, a lot of the injuries were multi-trauma. A lot of it involves long bone injuries, which a general surgeon doesn't normally deal with in Australia. Orthopaedics isn't part of our training, but you had to do that over there because you were the only surgeon."

MSF requires its surgeons to be available for at least six weeks for their first placements – war zones and disaster zones are common settings for short-term placements – but there are opportunities for much longer appointments too.

Hoffman recently returned from her second MSF mission, in Pakistan. In the two months she spent there, she treated 15 patients for gunshot wounds, 35 for burns and nine for land mines and explosives injuries. She conducted 17 general surgical procedures and 32 caesarean sections.

One of the challenges of providing obstetrics care in that environment (most of her work was obstetrics work), she says, is that many of the pregnant women arrive having received no antenatal care; their labours are also often in the advanced stages, due to the long distances they have travelled for medical attention.

She says some of the women arrived having fits and others had uncontrollable blood pressure. She delivered undiagnosed twins and triplets, and also delivered babies she knew had already died.

"By looking after the sorts of patients that you don't normally look after, it develops another skill set that you can then use in other situations," she says. "Unless you fall into a raving lunatic heap and you never do it again, it certainly builds your character."

Hoffman, an obesity and bowel specialist who works as a locum today, has previously worked as a private practitioner, university lecturer and medical officer, consulting to a public hospital.

Despite the intensity of her experiences with MSF, she says she doesn't lie awake overthinking them now she's back in Australia. What she has been contemplating, however, is what shape her next volunteer experience with MSF might take.

"I want to continue working locums here in Australia, but I would like to do another mission for MSF. Besides doing acute surgery, MSF also does a lot of reconstructive and rehabilitative surgery and I think that would be something I'd like to move towards too."