Thirty-six-year-old Indigenous man Ricky Hampson Jr - known to family and friends as Dougie - died less than 24 hours after being discharged from Dubbo hospital in NSW.

Doctors at the hospital treated the extreme abdominal pain he presented to the hospital with as if it were a rare marijuana-induced condition, however, it was later found out the pain was caused by lacerated ulcers in the stomach.

Mr Hampson Jr's family believe he would still be alive today had he received proper treatment.

Family members of Mr Hampson Jr left the court room on Wednesday, February 28, as a senior doctor at Dubbo hospital - who cannot be named for legal reasons - rose to make an apology to the family about the loss

"I wanted to say to the family that I'm very sorry for your loss and I wanted to say that I wish I could go back and change things," the doctor told the almost-empty gallery.

"It was a mistake and a tragic outcome that will sit with me for the rest of my life."

As the doctor was questioned on Wednesday, February 28, he admitted "cognitive bias" played a part in the deadly misdiagnosis.

The doctor told the court he first considered a diagnosis of cannabinoid hyperemesis syndrome (CHS) when he saw Mr Hampson Jr being wheeled into the isolation area of the hospital, before any examination took place.

He said he got this impression from the way Mr Hampson Jr appeared in his pain, which seemed similar to CHS patients he's seen at the hospital in the past.

"It was the body pattern, the movement, the agitation that triggered the thought it could be CHS," he told the court.

When the doctor later heard Mr Hampson Jr had smoked marijuana that morning it confirmed his hunch, despite the fact he didn't report nausea or vomiting normally associated with the condition.

Pressed on this by counsel assisting the coroner Simmoen Beckett, the doctor conceded "cognitive bias" played a part in the misdiagnosis.

"The brain works in weird ways which filters out information which is quite obvious," he said, red faced.

Although he acknowledged that a majority of patients he had seen with CHS were Indigenous, he denied that race played a role in his impression Mr Hampson Jr had the condition.

He said he now acknowledges there was no proper basis for the diagnosis.

"It is a matter of deep regret," the doctor told the court, wringing his hands and looking down at the bench.

On Tuesday, February 28, the inquest also heard from a young doctor who was under the senior doctor's supervision.

The young doctor told the court she examined Mr Hampson Jr and found he had a sudden onset of pain after feeling something pop inside his abdomen.

She said she conveyed this information to her supervisor and wrote it in the clinical notes. The popping felt by Mr Hampson Jr was also mentioned in triage notes written up by a nurse.

But the supervising doctor denies ever being told about Mr Hampson feeling a pop and says he didn't review the clinical notes or triage notes before making his diagnosis.

"If he said a popping or tearing it would have been completely different, but there was no mention of that," he said.

"It's not good news if someone mentions popping or tearing sensation in any part of the body.

"My first recollection of [hearing about the popping sensation] was when I was sitting down with my clinical lead... It was a shocking moment when I read it."

The doctor told the court after he spoke to the junior doctor about Mr Hampson Jr's case he performed his own physical examination. During this time he did not take a history of the pain or Mr Hampson Jr's cannabis use.

No record was made of the senior doctor's examination of Mr Hampson Jr. He also did not chart medication he suggested to treat Mr Hampson Jr.

Pressed on this, the senior doctor threw his hands up, conceding it was bad practice.

As the questioning of the senior doctor continued on Wednesday, February 28, he was further pressed on his claim that the junior didn't report the popping sensation.

"The difficulty is you've provided a first statement and second statement and neither of those mention popping other than when you recount the medical notes" Mr Beckett asked

"Yesterday was the first time that we heard you were not told about the popping and tearing ... if that was such a significant thing for a medical doctor, why did you not recall that in your first statement?"

The doctor shrugged.

He said he made an effort to review notes whenever he could, but when there is only one senior doctor looking over up to 65 patients he doesn't have a chance to review the notes on every one.

Counsel representing Mr Hampson Jr's partner asked the doctor why he thought Mr Hampson Jr was suffering from CHS on first appearance, without looking at the patient's history.

"You wouldn't think that someone would have CHS if they werent a cannabis user," she said.

"Yes that is correct," the doctor responded.

The coronial inquest into the death of Ricky Hampson Jr will continue at Dubbo court on Thursday, February 29.