"This was not a case of self-defence, this was not a case of defence of another person," Chris Taylor said during the crown closing address in the NSW Supreme Court on Thursday.

Blake Davis, 31, has pleaded not guilty to murdering Jett McKee whose head was sliced open with the sword shortly after the intruder fled the Forest Lodge unit on August 10, 2018.

His 26-year-old girlfriend, Hannah Quinn, denies being an accessory after the fact.

The judge previously directed the jury to acquit Quinn of murder, a charge which had been laid on the basis of being part of a joint criminal enterprise with her boyfriend.

The trial has been told the balaclava-clad Mr McKee had knuckledusters and a blank-firing pistol when he stormed into the unit with the intention of robbing the couple, who then chased him about 80 metres down the street.

Davis testified that the intruder pointed a gun at them and punched him before he woke up on the ground, heard his girlfriend screaming and thought "I have to save Hannah, I have to save Hannah".

Quinn told police Mr McKee "was holding the gun up at me" before he was struck with the sword.

Mr Taylor said even Mr McKee's family would say he deserved to be held accountable for what he did in the unit.

"The crown position is that he should have been dealt with for the crimes that he committed at 87A Hereford Street, but he was on his way out of 87A Hereford Street," he said.

He had been sprinting away and making his escape.

"Every step Mr McKee took, the risk he posed at 87A was a risk dissipated.

"The threat then became one which was actually posed to Jett McKee."

Mr Taylor cited evidence of Quinn being heard to say "what the f*** have you done?" after Davis brought the sword down on the would-be robber's head.

"A very telling choice of words you might think," the prosecutor said.

Quinn said nothing like "thank goodness you chopped him, my life was in danger dear".

None of the independent witnesses saw a gun being pointed by Mr McKee at Quinn or Davis immediately before he was struck, Mr Taylor said.

He attacked the credibility and honesty of Davis, referring to his saying he had no memory of using the sword at the time of the strike.

But he noted secretly recorded phone calls in which Davis said: "I tell everyone I can't remember ... I know exactly what was going on".

And his"false story" of having no memory would preclude him from saying he saw the gun being pointed at Quinn.

The jury has heard the couple stayed at hotels over the weekend before a solicitor arranged for them to go to a police station on Monday, August 13.

Referring to Quinn's accessory charge, the prosector noted she told police she did not know Mr McKee was dead until the day after the attack, the Saturday.

But Mr Taylor noted evidence of her being very close to the attack which witnesses described as bloody and of hearing a "loud clap" noise when the sword came down on Mr McKee's head.

The defence barristers are expected to address the jury on Friday.

Australian Associated Press