It might also be someone diving into a pool or river to rescue a swimmer in such difficulty that they would otherwise drown.

It’s the scenario of risking one’s life in order to save someone else’s.

But often it need not be so dramatic.

It can be as simple as signing up as a bone marrow donor.

Chris Baumann is one who has taken that step and he will be forever thankful that he did just that.

About 14 years ago he decided to put his name on the Australian Bone Marrow Donor Registry. It would be another 12 years before he came up as a match.

While that resulted in a lengthy process, he certainly has no regrets.

As he says, “I signed up so I could give someone else the same chance at the life I've got”.

His own mum’s battle with breast cancer certainly spurred him on.

The family of little Mia Yaldwyn know what it’s like to be on the other side of the donor equation.

The 12-month-old was diagnosed last May with acute lymphoblastic leukaemia.

It was especially heartbreaking for the family given that Mia’s grandparents Jeff and Ronis Lang lost their son, 10-year-old Daniel, to the same condition.

Finding a bone marrow donor for Mia became the absolute priority, in what Mr Lang describes as “the difference between life and death”.

She was able to be saved using stem cells from an Australian umbilical cord donation.

And in further positive news for the family, tests from just a couple of weeks ago show the transplant so far is doing what it was supposed to do.

For the wider community there can be no greater lesson from Mia’s journey than of how vital it is for people to become donors.

All they have to do is fill out a form when they donate blood at the Australian Red Cross Blood Service.

Mia’s other grandmother, Deanna Ballins, summed it all up perfectly.

“You can't describe what it's like to have her home, every precious smile and every time you cuddle her.

“I just want people to know they can save a life and it's a type of donation that no one needs to die for.”