Bickley said his and Paul's relationship had been "rocky" at the time of the crash.
On a return trip home to Waihī, Paul became upset and was arguing with him about his decision not to let her continue drinking with her friends in Whangamatā, Bickley said.
A "grumpy" Paul grabbed the steering wheel and tried to turn the station wagon into the path of a logging truck but he managed to regain control, he said.
A few seconds later, she grabbed the steering wheel again, this time with "a lot more force" and told him she was going to kill them both.
This caused the station wagon to swerve across the centreline and crash into the Hilux, he said.
Crown witness Helen Martelli, a registered nurse, todaytold the court she and her group were driving to Katikati when they came across the crash and she gave Paul and Bickley first aid.
Martelli said Paul, still strapped into the passenger seat, was semi-conscious, bleeding profusely from a wound on her head and was drifting in and out of consciousness.
"When the Māori lady [Paul] regained consciousness her first words were, 'f***, I caused the accident, it was my fault, it was my fault. It was words she repeated several times," Martelli said.
"I also remember her saying, 'I'm so sorry for what I did to those [other] people."
Martelli said she overheard Bickley saying to Paul: "Don't worry darling, we'll worry about that later."
Bickley, who appeared lucid, told her that he and Paul were returning home from an event and both had a "skinful", but it was his then-partner who had caused the crash.
The court heard that Bickley was found to be just under the adult blood alcohol limit.
Wendy Foster, a Hamilton teacher, said she had been travelling about 100m behind the station wagon for up to two minutes before it crashed.
Foster said she had seen it weaving in its lane before the driver appeared to regain control, but a few seconds later, it suddenly "rocketed" across the road.
"I felt so sorry for the oncoming vehicle as there was nothing it could do."
Crash analyst Constable Michael Chelley said there were two sets of distinctive yaw marks on the road which confirmed Bickley's vehicle slid sideways from left to right across the centre line, before hitting the Hilux.
To have left these yaw marks and gouges on the road, the station wagon had to be going between 67km/h to 73km/h at least, he said.
Bickley claimed his speed just before the collision was 60km/h.
Chelley said there were no visible signs of brake marks on the road before impact.
However, under cross-examination by Paul's lawyer, he conceded there was no way of knowing its exact speed before it crossed the rumble line or at the point of impact.
Senior Constable Jean-Marie Wright told the court she obtained formal statements from Paul and Bickley on February 5, 2017.
Wright said Paul, who sustained several injuries, including a knock to the head, claimed she had no memory of the crash nor recalled seeing a logging truck,
Paul stated she only drunk three cans of beer earlier that day, despite Bickley giving evidence the accused was drinking on the way home, she said.
Paul estimated Bickley's speed at about 70 km/h before the collision, Wright said.
The trial continues today, with the defence opening its case.
