Rotorua's Jason McMillan and his mates heard the sound of a boat crashing in darkness of the night, then the horrible noise of a revving engine that was clearly in trouble.
Two of them acted quickly, broke into a boat shed, stole a kayak and paddled into the darkness to help.
The drama unfolded on Friday night when McMillan was staying at a Marlborough Sounds resort for a wedding he was to be a groomsman at the next day.
He and a few of the bridal party and other guests were "a few beers in" when they heard the commotion on the water outside their rooms where they were drinking about 10.30pm.
McMillan and fellow wedding guest Ivan Whewell, both keen fishermen, went to the shore to have a listen and knew straight away something terrible had happened.
"If it was our boat, we knew it was only making that noise if s**t's hitting the fan."
As they prepared to leave, McMillan's partner, Jo Wilson, became a bit worried.
"She was saying 'are you sure you're alright'. We had all been drinking all night and you don't want to make it worse. But it was sobering hearing that noise ... we managed to get there and get it sorted."
McMillan said they found a boat shed on the shore and got inside by "being a bit rough with the gates", grabbed a double-hull kayak and started paddling towards the noise.
Whewell was paddling in the back and held his phone in his mouth with the light shining ahead.
"We could hear the sound of the crashed boat's engine getting louder and louder which was so scary because we couldn't even see the boat so we were just paddling towards a noise. We didn't even know how far out it was."
The father of two children, Robert, 2, and Thomas, 1, said they paddled about 500m and came across the boat crashed on rocks.
"It came into the phone light. Ivan jumped out and when he did we both fell out ... I swam over to the boat and by then Ivan was already on the boat."
Two men on board were in bad shape. One appeared unconscious and another was covered in blood and semi-conscious.
Somehow Whewell managed to kill the boat's motor by ripping out the ignition wires and managed to separate the battery from the motor.
"That most the important part because if that motor had kept going there were puddles of petrol all over the ground, if that went up, that's everyone gone."
McMillan used his T-shirt to help stop the bleeding from the man's head and tried to physically hold him down as he kept trying to get up in a disoriented and pained state.
"Just basic first aid and common sense took over. We knew to keep cool, we got this, do the basics and do it well."
Meanwhile, another wedding guest, Pete Butler, swam out and got help from a nearby dinghy.
That dinghy then towed the sinking boat to the resort's shore and they got the injured men off the boat and on to the jetty by using the resort's paddleboards. There, another wedding guest, who was a paramedic, helped the men until a rescue helicopter arrived.
They later heard one of the men suffered a fractured spine, fractured skull, damaged ribs and broken arms or wrists.
McMillan, who owns Aerial Solutions BOP based in Rotorua, joked that while he usually rescued people who didn't know how to work their televisions, he often found himself in sticky situations like this.
"One of the boys said to me these situations always find you."
But McMillan said the good turnout was a result of everyone pitching in.
"I couldn't have done it without Peter or Ivan. If it was just one of us or two of us, we wouldn't have had the same outcome."