James Gargasoulas, accused of killing six people and injuring dozens of others when he drove through Melbourne's bustling Bourke Street, plans to tell a jury his reason for the 2017 attack.
The 28-year-old mostly agrees with a prosecution case against him over the January 20 violence but has pleaded not guilty to six charges of murder and 27 of reckless conduct endangering life.
"Mr Gargasoulas, for better or for worse, is absolutely committed to his explanation," lawyer Theo Alexander told a Supreme Court jury on Thursday of his client's plan to take the witness stand.
Gargasoulas has a mental illness, but has been found fit to stand trial, and was in a drug-induced psychosis after using ice at the time of the rampage.
Dr Alexander said neither element defended the events outlined to the court by the prosecution, little of which he will dispute.
Director of Public Prosecutions Kerri Judd QC played graphic footage of the rampage to the courtroom, which was packed with victims and families.
There were audible gasps as the footage showed the first of 33 pedestrians was mowed down, followed by flying bodies.
"In a period lasting only about a minute during the busy lunchtime period, the accused left a trail of death and carnage along Bourke Street Mall," Ms Judd said.
He drove under shop awnings, where the number of pedestrians was greater, she noted.
The car eventually stopped, due to mechanical fault and being rammed by a police car.
Witnesses saw Gargasoulas appear to drive deliberately at people without hesitation and went out of his way to hit a pram containing a baby and toddler, Ms Judd said.
Those killed were three-month-old Zachary Matthew-Bryant, Tahlia Hakin, 10, Yosuke Kanno, 25, Jessica Mudie, 23, and 33-year-olds Matthew Si and Bhavita Patel.
Gargasoulas showed no emotion in court, occasionally reading.
In the lead up to the rampage, Ms Judd said Gargasoulas stabbed his younger brother, Angelo, repeatedly in the head and neck, causing life-threatening injuries.
Gargasoulas then led police on a 12-hour pursuit.
"I'm going to do something drastic, take everyone out. They will suffer the consequences. Watch me. You will see me tonight on the news. The police have stopped me before but they ain't going to get me this time," he told a friend.
Two strangers on the street called triple zero after Gargasoulas said they would see him on the news that night.
Police witness and long-time Melbourne detective Senior Constable Murray Gentner told the court Gargasoulas was an "attention seeker".
In text messages between the two on the day of the rampage, he said Gargasoulas believed he would "either die in jail or die trying to run from the boys".
"I sent a text saying 'don't be silly, I'll help you fix everything'," Snr Const Murray said.
Minutes later he followed Gargasoulas down Bourke St as pedestrians were thrown up to nine metres in the air.
"There was just so many people being hit. There were ones that were very clearly being struck," he said, pausing to blink back tears.
As Gargasoulas' car stopped, the detective pulled his gun and intended to "neutralise him". He was tasered and shot at twice - hit once - by other officers as arrested.
The trial continues.