When kitchen supervisor Paolo Vassallo escaped from the Lindt cafe six hours into the Martin Place siege, he urged police to storm the building, saying, "If you wait, someone is going to die in there."

Mr Vassallo, 37, also a chef, was one of the first three hostages to escape from the Martin Place cafe.

The siege began about 9.45am on December 15, 2014, after gunman Man Haron Monis pulled out a shotgun and told staff and patrons it was an attack by Islamic State.

On Friday, a distressed Mr Vassallo told an inquest into the siege that he escaped through a fire door off the kitchen and ran to waiting police.

"I said, 'You have to go in there,' " Mr Vassallo told counsel assisting the inquest Jeremy Gormly, SC.

"You can't wait for this guy. He's going to shoot someone; you can't wait, you have to go in. If you wait, someone is going to die in there," he said.

"I believed he would shoot someone."

But police did not storm the cafe until just under 11 hours later after Monis executed cafe manager Tori Johnson.

Hostage Katrina Dawson died from shrapnel from police bullets.

Mr Vassallo, a married father of two, told police that Monis claimed to have a bomb but he did not think that the claim rang true.

"I said [to police that] he said he had a bomb on him but from the way he was talking and acting, I didn't believe him," Mr Vassallo said.

"The police officer said, 'Look, Paolo, we can't just take your word for it,' " he said.

Mr Vassallo said Monis told the hostages "the government" didn't care if they died.

Asked by Mr Gormly if he believed Monis, Mr Vassallo said, "You'd like not to believe it but as the day went on you sort of did believe it [because] no one was coming."

Mr Vassallo also revealed he aborted one escape attempt after cafe worker Fiona Ma said "she couldn't leave people behind".

The duo had made a toilet stop via the kitchen and Mr Vassallo told her they were to leave via the emergency exit that led up a flight of stairs and on to Phillip Street.

But when Ms Ma, 19, refused to go, he abandoned his plan and went back into the cafe, because "I thought she would get shot and I didn't want that to happen".

Mr Vassallo later escaped via the emergency door seconds after barrister Stefan Balafoutis and retired tennis player John O'Brien squeezed through a partition and pressed the emergency exit button that opened the glass sliding doors on to Martin Place.

Under questioning from Johnson family barrister Gabrielle Bashir, SC, Mr Vassallo said Monis was becoming increasingly frustrated and angry that his demands were not being met.

He told the inquest he believed police had to take action or hostages would be killed.

"It was only going to go one way, it was only going to escalate, it was never going to be a happy ending, never.

"For anyone to think there was a chance of a peaceful resolution, that was never on the cards."

He said he wanted police to "end it on their terms" so he remaining hostages would have had "half a chance, a chance".

"To end like that - it kills me."

Earlier on Friday Mr Vassallo said Mr Johnson was a "good guy".

"He was a manager and he was a friend - not many people can do that."

Under questioning from the Dawson family's barrister Phillip Boulten, SC, Mr Vassallo said his "main message" to police upon his escape was to "go in now".

"I said, 'What are you guys doing? Peaceful resolution is out of the question ... there's people in there I care about."

Wiping away tears, Mr Vassallo said he escaped so he could assist police end the siege.

"I didn't want to leave there without making a difference, I had to make a difference," he said.

"Me leaving was about providing police as much information so they could do what they had to do, or at least ask questions," he said.

Mr Vassallo revealed he had returned to the Lindt cafe once but has not been able to work there, or anywhere else, since the siege.

The inquest before coroner Michael Barnes continues.