Lucas Tattersall, who was travelling with Jayden to a New Year's Eve party in Cairns in December 2017, said he was "off" his head on ecstasy and hadn't slept for days when he drove away and left his friend after he stormed off following an argument on a stifling hot morning outside the Far North Queensland town.

He told a Cairns-based inquest Jayden angrily walked away from the car after he lost a large bag of methamphetamine, or ice, that he had bought on credit, and had been smoking throughout the 2300km road trip that the pair planned to do in a day.

According to Mr Tattersall, Jayden said: "You don't know what these people are going to do to me for losing all these drugs."

He said Jayden, who was driving at the time, had pulled over "up to eight or nine times" and was frantically searching the car and bags looking for the ice.

The court heard when he couldn't find the drugs, the argument escalated to the point where Mr Tattersall said Jayden threatened him.

"I wasn't raised to fight, I was raised to kill," Mr Tattersall said Jayden yelled at him after they stopped on the side of a remote road off the Flinders Highway early on the morning of December 31.

Mr Tattersall said he yelled back because he was "sick of getting treated like a piece of shit".

"I hadn't done anything wrong," he told the court.

"I was anxious. I was scared. I wasn't going to fight him."

He then said Jayden grabbed his stash of MDMA powder, smashed his phone and walked off.

NQUEST:

Mr Tattersall said he tried to follow Jayden but his friend yelled at him that he wanted to be left alone.

He told the court he sat in his car listening to music for up to 15 minutes, in an effort to calm down, and then went to look for Jayden.

"I didn't assume anything bad was going to happen. I started calling out his name. 'Jayden! Jayden!'" he said.

"My heart started to race a bit more, I started yelling and screaming his name out. I couldn't find him."

Mr Tattersall denied trying to minimise his involvement in Jayden's disapperance, but agreed his version of events at the inquest wasn't the same as what he told police in three different interviews after Jayden went missing.

When asked by counsel assisting Joseph Crawfoot if he assaulted Jayden, Mr Tattersall replied: "No."

He told the court he searched for some time and drove up and down the road looking for Jayden but couldn't find him.

Mr Tattersall said he pulled into a nearby property and asked for water and if anyone had seen Jayden.

But on Tuesday, Charters Towers resident Lionel Murphy gave evidence that a flustered and "bit shifty" looking Mr Tattersall asked him for water, but never mentioned his friend or that anyone was missing.

Mr Murphy said he claimed to be looking for a property.

The court heard accusations that Mr Tattersall's evidence was riddled with inconsistencies. He said Jayden had not yet lost the drugs when the pair were caught on CCTV at the Puma roadhouse outside Charters Towers in the early hours of the morning Jayden vanished.

But when played the footage on Wednesday afternoon, Mr Tattersall was at a loss to explain why Jayden was seen on the vision frantically searching through the car.

When asked why he didn't immediately report Jayden's disappearance, or contact police when he reached Cairns later that night, Mr Tattersall said he "didn't want to be a rat" because his friend was carrying drugs.

He said the pair had not slept in days and the morning was quickly heating up, the temperature would eventually reach 39.1 degrees.

After several hours when he couldn't find Jayden, Mr Tattersall claimed other people already in Cairns told him to continue on driving.

But Jayden's cousin and good friend Tim Westcott told the court on Wednesday the friends told Mr Tattersall to turn around and keep looking for Jayden.

When he got another text hours later saying there was no sign of Jayden, he messaged Mr Tattersall, who he had never met, and told him that there was a bed for him in Cairns.

Mr Westcott, who invited Jayden on the trip to Cairns, said he had no idea at the time Jayden had gone missing in a remote location.

In an exchange of text messages after Jayden walked off, Mr Westcott said he initially told Mr Tattersall not to go to the police because he didn't want to get Jayden in trouble.

"I was never made aware of the seriousness of where he was left," he said.

"I thought he was driving up the coast. I didn't event know where Charters Towers was ... I wasn't made aware he went missing in the middle of nowhere."

The court heard the group of about 16 Newcastle men kept partying and drinking for several days before Jayden was eventually reported missing on January 3.

An emotional Mr Westcott said he had to "live" with the mistakes he made, but said he thought Jayden had his phone and wallet when he went missing.

It wasn't until he "physically Googled" Charters Towers that he realised Jayden could be in trouble.

"I thought he would have been able to go a train station," he said.

"This is the guilt I have to go through. It's what I've got to live with."

Exactly what happened to Jayden after Mr Tattersall drove away no one can say for sure.

The inquest into Jayden's disappearance entered its second day on Wednesday, hearing evidence from several Newcastle men who travelled to Cairns for the New Year's celebrations.

Queensland Coroner Nerida Wilson is tasked with determining whether Jayden is dead, and if so, when and how he died.

Under heavy questioning from Jayden's mother's barrister, Alex Raeburn, about the different versions of events he had given, Mr Tattersall said he initially told police "what he thought they needed to know".

He said his memory was "cloudy" due to sleep deprivation and because he had consumed MDMA powder and several ecstasy pills.

He also disclosed that Jayden purchased an ounce of MDMA powder, or 28 grams, and half an ounce of ice from some men he met in the carpark of the Hoyts cinema complex at Charlestown before he left on the road trip.

Mr Tattersall, who has previously never spoken publicly about Jayden's disappearance, said he waited in his car for about 90 minutes at Charlestown while Jayden got in another car to buy the drugs.

He told the inquest that Jayden bought the drugs "on tick", or credit, in a "buy now, pay later" arrangement.

The court heard the ounce of MDMA cost $2200 and Mr Tattersall said he was unsure how much the ice cost, but said it "wasn't cheap".

Mr Tattersall said he purchased 100 ecstasy pills for around $700 to take on the trip that he planned to sell to Jayden's mates in Cairns.

Mr Tattersal said he'd been friends with Jayden for about 18 months and they used to hang out together after work.

The pair started their trip to Cairns on December 29, with the plan to drive straight with no sleep to make the New Year's Eve celebrations.

They took ecstasy pills, and Mr Tattersall said Jayden was smoking ice regularly throughout the journey, to the point where he was stopping to smoke ice every three or fours hours.

"It was good, we were both high," he said.

"At this point he [Jayden] was in a real good mood. Nothing mattered, it was all good."

But he said Jayden became increasingly agitated and paranoid and the trip "turned to shit" when he believed he lost his drugs at Charters Towers.

Detective Sergeant Peter Edwards, who led the missing persons investigation, said he did not believe foul play was involved.

Police believe that Jayden perished after getting lost in the bush during stiflingly hot summer days that reached over 40 degrees at Charters Towers.

Det Sgt Edwards said Mr Tattersall had cooperated with police and willingly gave his time attempting to locate where he last saw Jayden, his phone and car for forensic analysis.

He said "with the information I have so far", he does not consider Mr Tattersall a suspect in the case.

"He appeared very cooperative, trying to do the best he could to try and locate where he last saw Jayden," he said.

Jayden's mother, Rachel Penno, told the inquest on Tuesday that she believed her son was murdered.

She said that Jayden had received threats in the weeks before going to Cairns from a man linked to Mr Tattersall over drug debts.

She believed Jayden also owed $3000 to the Finks outlaw motorcyle club.

Earlier in the day, the inquest heard Jayden and his Newcastle mates, who travelled to Cairns for a New Year's Eve "bender", were part of a Facebook group called the Deadbeat Drug Camp.

The men said the social media chat group had been set up as a joke when they were younger and the name stuck.

Friend Jed Wakefield said some members of the group met at a Lake Macquarie pub to discuss the boys' trip and Jayden "put his hand up" to drive the drugs to Cairns because everyone else was flying.

Mr Wakefield said he first met Mr Tattersall, who wasn't a member of the Facebook group, in Cairns when he arrived without Jayden, and he looked "fried" and "cooked".

"He looked pretty scattered, he looked like he'd been awake for a while," he said.

"He looked a bit nervous to be honest."

Another Newcastle friend, Callam McDougall, said the trip was a holiday, not a "drug trip".

Mr Tattersall will resume giving evidence on Thursday.

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