Roser, 63, is on trial for murder after Bruce Saunders died while working on a property north of Brisbane in November 2017.
The Crown alleges Sharon Graham asked her lovers Roser and Peter Koenig to kill her ex-partner Mr Saunders, 54, and make it look like an accident in a bid to claim his $750,000 life insurance.
Footage has been shown to a Brisbane Supreme Court jury of Mr Saunders' legs protruding from the chipper at the Goomboorian property near Gympie after clearing trees with Roser and Koenig.
Roser can be heard discussing with Graham differences in his statements among hours of police audio from listening devices at a Nambour residence.
Graham, 61, first suggests Roser approach his lawyer in a February 2018 conversation.
"You have actually incriminated yourself to be put on charges which is totally not right," Graham said in audio played to the jury on Thursday.
"So what's happening now you need to tell a lawyer 'I f***ed up with my statements ... because the day of it happening I have a total block'.
"'Something has blocked my head. It's a wonder I was able to give a statement'."
Reflecting on what he told police, Roser says there are inconsistencies about where he was when he claimed he first saw Mr Saunders in the chipper.
Graham then reminds Roser that police could not find footprints where he claimed he stood in his bid to "save" Mr Saunders from the chipper.
"That definitely caught you," she said.
Roser replies: "I f***ed up there.
"I am about 90 per cent I did not put one foot on the tail gate at all. I tried to pull him out while I was standing on the ground."
Graham then whispers: "If you put your foot up you are bracing yourself to pull stronger".
Graham adds: "In shock you would say a lot of things that were not right."
Roser blamed the police for his inconsistencies.
"Because you know what they do they interrupt you all the time ... and it f***s you up," he said.
"I had in my mind something and then he (police) started talking ... that's what they kept doing to me."
The couple start looking up side effects for his pain medication.
Roser tells Graham that one causes "dizziness and light-headedness".
"You can't judge things ... you can't judge distances, it throws you out," he said.
Graham tells Roser to approach his doctor and say the medication's serious side effects had led to confusing police statements.
She then discovers they are reading the medication's withdrawal symptoms.
"OK what is the next drug that you want to look up?" she asks.
Roser then says: "Here we go, this one ... I know I have got that - disorientation."
"What's disorientation mean?" Graham asks.
"It means you can't make decisions, you get really confused about things ... you don't know where you are and you can't judge things," Roser replies.
Graham then tells Roser: "The doctor has to put all of this in writing for you."
Graham - who has successfully applied for a separate trial - and Roser have pleaded not guilty to murder.
Roser's trial before Justice Martin Burns continues on Monday.
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