As Lucas Fraser approached the scene of a van wreck he was certain the driver was dead.
But with 10 years' nursing experience, Fraser knew he had to double-check.
He pushed the driver's jaw back and tilted his head slightly to open his airway and as he did that, the man took a deep breath.
"The side of the van that I went to was missing and the roof was missing. The gentleman was hanging out of the vehicle and he did look dead," Fraser said.
"There was a truck driver there, he said, 'don't go up, he's dead, he's dead'."
The Waikato Hospital duty nurse manager held the man's airway open to keep him alive as he sat critically injured in the wreckage.
He has experience in ICU and the emergency department and said he "kind of kicked into work mode".
Paramedics arrived 10-minutes later and he then helped transport the injured driver to an ambulance.
Fraser, 30, was heading from his home in Karapiro to work in Hamilton when he came across the two-car crash on the Waikato Expressway. The crash happened about 6.40am on Wednesday.
He saw another vehicle - a truck - flipped on its roof but he stayed with the 24-year-old van driver as he was unable to breathe on his own.
A white work van travelling south towards Cambridge appeared to have crossed the centreline, on the expressway near Bollard Rd in Tamahere, and struck the light truck heading north head-on, Senior Sergeant Will Loughrin said from the scene on Wednesday.
The truck has then rolled over a concrete barrier in the left hand lane where construction is underway on the expressway.
The van ended up in the middle of the road while the light truck was smashed over the concrete barrier.
Rohit Gupta had just dropped his wife at work and was heading back towards Hamilton when the crash unfolded.
"The guy in the van was really injured, looked like half his leg was broken."
Gupta watched as Fraser gave medical assistance to the driver of the van.
"You could see the driver of the van…he was breathing but unconscious, most of his body looked broken. There was blood everywhere.
"It was good the guy was there and could give him first aid, keeping him alive.
"He's a real hero to me."
Others were helping the trapped truck driver but Gupta said they were initially unable to reach him.
Firefighters arrived and cut both men from the wreck.
Both the van driver and the 25-year-old man driving the light truck were injured and on Wednesday afternoon were in a critical condition in Waikato Hospital's ICU.
"The firefighters were really good in helping the truck driver. They had a pipe to help him breathe and then put him on a stretcher."
Police shut down the road for about four hours and diversions were in place at the Tamahere Interchange and the Hillcrest roundabout. The road re-opened at 11am.
Loughrin said police were continuing investigations into the causes of the crash.
The crash was one of several in the Waikato overnight that left a total of five people seriously injured.
Two people were left seriously injured in a second crash at Collins Rd and Tuhikaramea Rd south of Templeview on Wednesday morning.
There was heavy fog in the area of the crash around 6am, Senior Sergeant Simon Cherry said.
One person was trapped in the vehicle and subsequently freed before being taken to a waiting ambulance.
That person was in a serious condition and was taken to Waikato Hospital, a St John spokesperson said.
One other was understood to have moderate injuries was also taken to hospital for assessment.
It was the second crash of the night after a truck and trailer carrying a load of tomatoes crashed near Pirongia.
The truck ended up on its side and took out powerlines on Ormsby Rd just after midnight, Fire and Emergency northern communications shift manager Craig Dally said.
The driver wasn't trapped but reportedly suffered serious injuries and was taken to Waikato Hospital.
Crews from Hamilton, Pirongia and Te Awamutu attended.