A man did nothing to prevent the deaths of two people and ignored a desperate plea for help as the pair were locked into a large metal toolbox in which they were later found dead, a Brisbane court has heard.

Seven men and a woman have been charged with the murders of Cory Breton, 28, and Iuliana Triscaru, 31.

Their bodies were found in February 2016, 18 days after they were last seen alive.

They were locked in a large metal box that had been submerged in a dam in Kingston, south of Brisbane.

Lelan Harrington said he went to buy drinks for the alleged killers. ( Supplied: QPS )

The Magistrates Court heard harrowing evidence of the victims' final moments alive.

Under cross-examination from Angus Edwards, lawyer for one of the defendants, witness Lelan Harrington admitted he was buying soft drink and cigarettes for the alleged killers when he could have called police to say the victims were tied up inside a house.

Mr Edwards asked: "As Mr Breton got into the box, he looked at you and said to you, 'help me, I'm going to die'?"

Mr Harrington replied: "Yeah."

Mr Edwards: "Did you help him at all? You mopped up the blood, didn't you?"

The court heard Mr Harrington was at a house on Dewar Road in Kingston when he was asked by defendant Stou Daniels to call Mr Breton and invite him to visit.

Mr Harrington said he went upstairs in the house a short time later and saw someone in the house with a pump-action rifle.

Edwards: When you asked about that firearm, you were told it was going to be used to scare Cory Breton weren't you? Harrington: Yeah. Edwards: Did you try and ring Cory Breton to tell him not come around? Harrington: I didn't have a phone. Edwards: Did you ask for a phone? Did you ask to borrow Stou's phone to make a call? Harrington: No. Edwards: Did you try to leave the house to go and make a call somewhere else? Harrington: No. Edwards: You did nothing to try and warn Corey Breton that he was going to be scared with a shotgun?

The court heard Mr Harrington came downstairs after some time and Mr Breton was bleeding from his leg as he and Ms Triscaru were tied up on the couch.

Police found a metal box containing the bodies in a dam at Kingston. ( AAP: Dan Peled )

Mr Harrington admitted to helping bind Ms Triscaru back up after someone cut the duct tape binding her, before he went to a nearby service station to buy drinks for the group.

"Did you try to make a phone call then to the police or to anyone to try and get help for Cory Breton or Ms Triscaru?" Mr Edwards asked.

"No," Mr Harrington replied.

"No-one would have seen you if you'd done that, would they?" Mr Edwards asked.

"No," Mr Harrington replied.

Mr Harrington told the court he was afraid of Mr Daniels, but also admitted to smoking the drug ice on the day.

When Mr Harrington came back from the service station the victims were asked to get into the box in which they were found dead.

Two men, Tuhirangi-Thomas Tahiata and Trent Thrupp have been committed to stand trial on two counts of murder.

A decision is yet to be made on whether Mr Daniels, Webbstar Latu, Ngatokoona Mareiti, Tepuna Mariri, Davy Taiao and Waylon Ngaketo Cowan Walker will also stand trial for murder.

Witness accused of lying about shootings

Barrister John Fraser, acting for Mr Daniels, accused Mr Harrington of lying during police interviews about his client.

"Stou in your presence never said, 'let's kill them, let's hurt them', you agree with that?" Mr Fraser asked.

Mr Harrington replied: "Yes."

Mr Fraser suggested Mr Harrington lied to police when he told them Mr Breton and Ms Triscaru were shot by defendant Trent Thrupp.

Police at the vacant site where the metal toolbox was found. ( ABC News: Nick Castellaro )

Mr Harrington admitted he did not witness any shootings.

Mr Fraser replied: "So that was another lie? Why would you say that?"

"Because that is what I thought," Mr Harrington said.

Mr Harrington also disputed Mr Fraser's suggestion it was "nonsense" for Mr Harrington to claim Mr Thrupp shot the pair in the head when he had not witnessed it.

"You told police they might be alive," Mr Fraser said.

Mr Harrington said that was because "I did not believe they were missing until I saw the news".

Mr Harrington later told the court he was afraid he would be charged with murder.