Pilot Graeme Gale said about 220 people celebrated the helicopter service's 21st birthday at Toitu Otago Settlers Museum on Saturday.
The helicopter was flown to the event and was parked near the museum entrance but had to leave the celebration about midnight to attend a serious crash in the Hakataramea Valley.
Six people were injured - two critically - after a Toyota Land Cruiser left the road and rolled.
The helicopter made two trips to take one of the critically injured victims and a seriously injured one to Dunedin Hospital, while Westpac Rescue Helicopter from Christchurch took one person in a critical condition and another in a serious condition to Christchurch.
The other two occupants were both seriously injured and taken by ambulance to Timaru Hospital.
Sergeant Mike van der Heyden, of Waimate, said the people in the Land Cruiser were all from the Kurow Waimate area and aged between 22 and 39 years.
The seven seater Land Cruiser was just east of Cattle Creek when it failed to take a moderate left hand bend.
The driver lost control, veered across the road, then over corrected. After leaving the road, it rolled at least twice. It was the only vehicle involved.
Sgt van der Heyden understood all the occupants were thrown from the Land Cruiser and it was too soon to say what caused the initial loss of control, whether occupants were wearing seat belts and whether speed or alcohol were factors.
Mr Gale said the night at the museum paid tribute to the helicopter and the people who had made the service a success, including pilots, doctors, nurses, paramedics, engineers, ground crew, office staff and sponsors.
''The people who never get a mention - never get a credit for anything - yet they are a vital part of the whole service.''
To allow everyone involved with the helicopter's success to enjoy the ''fantastic'' celebration, Garden City Helicopters, the business operating Westpac Rescue Helicopter from Christchurch, supplied pilot Tim Douglas Clifford to cover some of the weekend's work.
The celebration was the first time everybody involved with the helicopter had a night without being on call, he said.
Mr Gale said the helicopter had flown nine missions within 24 hours from Saturday morning including the Hakataramea Valley crash, flying a man in a critical condition from Wanaka, winching a fisherman from a boat after he had been swept off rocks and winching a man from Tunnel Beach.
St John Coastal Otago territory manager Doug Third said a Northland man, aged in his 20s, sustained a moderate back injury after jumping in the water from a headland about 1pm on Saturday.
The man was winched to the Otago Regional Rescue Helicopter and flown to Dunedin Hospital. His condition was not known last night.
