Accused Bourke St driver James "Dimitrious" Gargasoulas believes he will have access to women and the internet if he goes to a psychiatric hospital in Melbourne rather than prison.
Gargasoulas is facing an investigation hearing before a jury in the Victorian Supreme Court to determine if he is fit to stand trial on six counts of murder and 28 charges of attempted murder over the January 20, 2017 rampage.
Four medical experts have told the hearing the 28-year-old suffers from schizophrenia.
Forensicare consultant psychiatrist Andrew Carroll on Thursday said he believed Gargasoulas was unfit for trial. He is the second psychiatrist to make that conclusion.
But psychologist Michael Daffern thinks Gargasoulas is fit to stand trial despite his schizophrenia.
"He does have these delusional beliefs and truly believes he is the saviour," Professor Daffern said.
"I don't believe that these delusional beliefs are overwhelmingly undermining his capacity to make a logical decision in relation to a plea."
In his report, Prof Daffern concluded Gargasoulas was "invested in securing a disposition that would permit a release from custody".
The psychologist said Gargasoulas was interested in being sent to Thomas Embling pyschiatric hospital rather than remain in prison, where he was on 23-hour lockdown.
"He told me that he thought he might be able to access the internet, there might be access to a mobile telephone," Prof Daffern said.
"He was also interested there would be females at Thomas Embling Hospital as well."
Earlier on Thursday, Dr Carroll said Gargasoulas had expressed a desire to stand trial so he could tell people he was the Messiah.
"He absolutely wanted to make sure he had a trial of some kind so that he has a public platform (for his Messianic beliefs) so the public can ask questions about why these events happened," the psychiatrist said.
"In his mind he believes that would lead to some kind of uprising and save the planet."
Dr Carroll added Gargasoulas has an unrealistic belief he will be released from custody after spending five years at Thomas Embling psychiatric hospital.
While Dr Carroll believes Gargasoulas' reasoning is heavily influenced and compromised by his delusional beliefs, Prof Daffern thinks Gargasoulas can make decisions that are unaffected by his delusions.
The hearing before Justice Lex Lasry will resume on Friday.