Mr McClean was equally selfless when a group from Elim Christian College was confronted by the swollen waters of the Mangatepopo River.
The 29-year-old teacher strapped a disabled pupil to him, an act that, according to rescuers, severely reduced his chance of reaching the side of the river before being hurled over a dam.
In an ideal world, people who have the strength to respond this way to extremely dangerous situations would survive and be feted.
Curiously, however, the deaths of Mr Hemmings and Mr McClean triggered a more personal response.
People want such honourable sacrifice to have a consequence. Many not only wondered whether they would do the right thing in similar circumstances but, after a period of introspection and re-evaluation, willed it to be so. Effectively, they shunned a society in which helping a stranger was regarded as unusual or intrusive, and condemned the apathy of those who choose to be passers-by.
Mr Hemmings and Mr McClean would have appreciated that legacy. A mourner at Mr Hemmings' funeral spoke of his high integrity, strong moral fibre and wish to change society for the better. Similarly, Mr McClean's father spoke of his wish that "hope and goodness can come out of something traumatic and awful."
When a deed is as inspiring as that of his son, and of Mr Hemmings, such sentiments cannot but have enduring resonance.
From the Herald archives:
'New Zealanders of the year', NZ Herald online, 6 December 2008
'Two deaths that made life precious', NZ Herald online, 6 December 2008