Radio calls about a knife-wielding woman shot dead by police near a Sydney fast-food restaurant told responding officers she was talking to herself and had a large knife pointed at her stomach, an inquest has heard.

Senior constable Paul Falzon told the Glebe coroners court on Thursday that, when he heard these calls, mental health or drug issues came to mind.

“I believe she may have been drug affected or there may have been other issues,” he said. “We tried to attend as quickly as we could.”

The inquest is investigating the death of Courtney Topic, who was shot by an officer near the West Hoxton Hungry Jack’s car park in February 2015.

The court heard Topic had probably been experiencing an untreated psychosis for a sustained period of time and likely suffered from undiagnosed schizophrenia.

Police radio calls on the day of her death reveal responding officers were told the “distressed” woman was “talking to herself” and pointing a large carving knife at her stomach.

Police at the Hungry Jack’s in West Hoxton, south of Sydney. Photograph: Dan Himbrechts/AAP

They also heard the young woman in a striped top and jeans was “waving” the knife about and “hitting herself in the head”.

There was concern Topic was about to hurt herself.

Despite this, senior police had not contacted Falzon to respond as an accredited member of the police mental health intervention team.

The 12-year veteran had only reacted to the urgent priority-two call in a general duties capacity.

He said that, since receiving the training in 2014, he had never been contacted by senior officers to employ his MHIT training.

Sitting beside him, his partner, Constable Sanja Djuric, was unaware he had received the mental health training, which included de-escalation skills when approaching someone with a dangerous weapon.

They did not discuss the possibility that Topic could have been suffering from mental illness as they rushed to find the young woman moving through the suburb of Carnes Hill with “a large carving knife”, according to their radio.

As the pair arrived at Hungry Jack’s at the intersection of Cowpasture and Hoxton Park roads, Topic was already surrounded by three police officers and the situation was spiralling out of control.

The senior constable arrived seconds too late to use his training and help the 22-year-old.

He watched as Topic was pepper sprayed and then shot in the chest after she moved towards one of the officers who was attempting to back away.

Falzon held the young woman’s head as she lay dying while fellow officers attempted first aid.

Topic’s family thanked the policeman for helping Courtney in her final moments.

The inquest continues.