Joelene Joyce saw her partner gunned down on a dark and lonely NSW country road before desperately running for her life, even after she had been seriously wounded by the assailant.
Daniel Poynton continued to chase the terrified woman in the darkness, hitting her in the head with the shotgun after she turned to lunge at him with a large hunting knife.
"That caused her to fall to the ground, where she was shot again, suffering further injury, before finally making her way back to the car, where she died helpless and alone," said Justice Monika Schmidt on Thursday in the NSW Supreme Court.
Describing her death and that of Jamie Edwards' as "needless, painful and lonely", the judge jailed Poynton, now 25, for at least 18-and-a-half years for their murders.
Poynton, 21 at the time, pleaded guilty in June to murdering the two 36-year-olds, who were found dead in a car by a passing motorist near Moama, on the NSW and Victoria border, on November 12, 2014.
According to the agreed facts, Poynton and Mr Edwards had been close friends and drug supply associates in a network that predominantly supplied the drug ice around the Echuca township, in Victoria, also near the border.
"Their relationship had soured over a robbery of the drug ice from another person, which had resulted in both Mr Poynton and Mr Edwards being threatened by others," the facts said.
The men had agreed to meet in the early hours of the morning on a road near Moama, Poynton claiming it was because he was interested in buying ice and a gun from Mr Edwards.
Poynton told police he arrived on a trail bike with a shotgun hidden under black clothing because he was worried he was going to get "hit".
The meeting ended in Poynton saying "Hey bud!" before shooting Mr Edwards through the car window as he sat in the driver's seat with the seat belt on.
He then went on to execute Ms Joyce.
The judge found Poynton was undoubtedly paranoid at the time, affected by both his long-term mental illness and the ice he had taken.
He had a difficult background and had long suffered considerable mental health problems, having a history of self-harming behaviour, of auditory hallucinations and drug and alcohol abuse problems.
The judge referred to the "moving" victim impact statements provided by relatives of the two victims, noting the ongoing sadness and grief which "these awful offences have caused".
She accepted Poynton was genuinely remorseful.
But she found he presented "a considerable ongoing danger to the public, given the nature of his mental illness and the serious adverse impact which his past significant substance abuse has had on his behaviour".
The judge set a maximum term of 24 years and nine months.