Emergency services staff were traumatised when a patient was killed after jumping out of the back of an ambulance and running into the path of an oncoming truck south of Hastings.
Police said the ambulance had stopped on the side of the road near Te Hauke about 4.40pm. The man jumped out of the back door and ran across the road, straight into the path of the truck. He died at the scene.
The man had earlier been picked up by a St John ambulance from the Waipukurau police station and was being transported to Hawkes Bay Hospital for treatment.
St John Hawkes Bay district-operations manager Stephen Smith said the ambulance, which had a Hawkes Bay District Health Board escort and a St John ambulance officer on board, had encountered another ambulance returning to Waipukurau.
The ambulance carrying the patient stopped on one side of the road and the other ambulance had stopped on the other, "to see if everything was all right".
At this point, the man climbed out of the ambulance.
"Somehow he got out, our staff tried to corral him in, but he broke through them and on to the road," Mr Smith said.
"We have ambulance staff who have been deeply affected by this and we're working with police to find out what has happened."
A Hawkes Bay DHB spokeswoman said the death had been referred to the coroner.
Hawkes Bay road-policing Senior Sergeant Greg Brown said ambulance, health staff and the truck driver were all "very shaken" after the incident and had received help from Victim Support.
"It was a very traumatic event for all concerned."
The "very experienced" Russell Roads truck driver, who had been with the firm for 25 years, was reeling after the incident, said company owner Chris Russell: "He's very, very shaken up. He's just devastated. It's going to take a lot to get over it."
Police closed SH2 between Waipawa and Hastings for three hours during peak traffic, with diversions in place north and south of the crash scene.
When the man arrived at the Waipukurau police station it was thought he might have ingested petrol earlier and the ambulance was called to treat him.
It was the third Hawkes Bay road death in five days and brought the road toll for the region to 19, according to figures released by the Ministry of Transport. That was more than three times last year's road toll of six deaths.