Dusk was settling as we headed back from the old prison settlement of Port Arthur towards Hobart. Autumn trees blazed like frozen fireworks against amethyst hills.

There’s something familiar to the New Zealand psyche about Tasmanian roads. Unlike Australia’s straight, wide belts of motorway, they twitch and bend like nerve cells through the landscape.

Rounding a sharp corner, we were suddenly confronted with a series of impressions – a figure lying on the side of the road alongside a battered motorbike, its engine still revving, its headlight gazing vacantly into the bush, a crumpled yellow L plate on its mudguard.

People often talk about time slowing down in these situations. From the passenger seat, it seemed the opposite. Events were unravelling with the windup speed of an old Charlie Chaplain movie.

Another car had stopped in front of us. In a single movement my husband pulled up behind, leapt out and ran towards to the prone figure. I was about to do the same – then suddenly remembered our 13 year-old in the back seat. She’s overly sensitive at the best of times.

Besides, other cars were already stopping behind us and people were rushing forward. The victim was in danger of being mobbed. I prayed someone on the scene had medical training.

To everyone’s relief he (for it was a young man despite the fine facial features and long hair) was still conscious –though ashen, trembling and suffering terrible pain and bleeding from one leg.

My husband and the woman hitched the victim’s arms over their shoulders and inched towards her car. In the smoky twilight they looked like a trio from a war painting of two soldiers supporting a wounded comrade. But the pain of being moved was unbearable. They laid him back down on the side of the road.

While mobile phones are a pest 99% of the time, occasionally they’re invaluable. The local ambulance people were having a busy night, however.

They said we’d have to wait for an ambulance to arrive from Hobart 90km away. Even with my appalling maths, I could work out we were in for the long haul, at least an hour’s wait. The alternative of abandoning a frightened young man with his pain on the side of the road was unthinkable.

The woman from the car in front, Robyn was her name, and my husband had already created a bond with Tom, who needed all the comfort and reassurance he could get. Watching my husband stroking the boy’s hair and talking gently to him reminded me how fortunate I am to live with such a human.

Robyn had a brisk motherly approach which suited Tom. He was only 17, after all, and resting between girlfriends. She kept reminding him how lucky he was – which technically speaking, he was.

Robyn works in the gift shop at Port Arthur. It seemed ironic Tom should have received the gift of a guardian angel from the Port Arthur gift shop that night.

Around us a sort of order seemed to be forming almost effortlessly. A bloke who said he was a mate, took the crippled motorbike away in the back of his ute. Without noise or fuss, other men set up points at either sides of the corner warning traffic to slow down.

People stopped and gave what they could. A woman draped a towel over Tom before running away. Someone, more usefully, donated a foil blanket which seemed to retain Tom’s body heat efficiently.

Cars crawled past – maybe several hundred of them. Very few stared with the heartless curiosity of rubber neckers. Many wound their windows down and asked if they could help. Not one was a nurse or doctor.

Hearing gentle sobbing from the back seat, I asked what the matter was.

“I thought people were cruel and selfish,” the teenager said. “But everyone’s being so generous and caring. It’s unbelievable.”

A couple of Tom’s motorcycling mates turned up to keep vigil with us.

“Ran out of road, did you mate?” one of them asked Tom, who managed a smile.

We were all delighted when a bloke arrived with a small suitcase and professional smile. An off-duty paramedic. He had no painkillers, unfortunately, but set Tom up with a drip, and at last gave me a job – holding the fluid bag.

The ambulance finally arrived with Tom’s anxious parents in its wake. The driver asked if we were friends or family. Over the past hour it felt like we’d become both.

After brief hesitation we said no.