I did mean Wellington, LifeFlight and Westpac have bases there and are on 24 hrs standby. If needed, they could have airlifted medical staff and supplies to Blenhiem on the way out.
They would have done a triage on the patients first if there was a big incident, sorting out the worst off to the best, treating accordingly. Then the aircraft could have flown them out to Wellington or Nelson as needed.
I also suspect that Base Woodbourne would also have good medical facilities, being a major RNZAF base..