Police lacked confidence in the force's pursuit policy at the time they were chasing the delusional and erratic Bourke Street driver before he mowed down pedestrians in Melbourne's CBD.
Detective Senior Constable Murray Gentner told the third day of an inquest into the January 20, 2017 tragedy police overwhelmingly felt "hamstrung" when it came to pursuits.
"There was a degree of hesitation," he said, following a member being charged with ramming a stolen car.
There were concerns chases at that time could "land you in hot water".
He said pursuit rule changes introduced this year potentially "freed us up to police in a more natural way again".
Det Sen Const Gentner came under scrutiny on Wednesday over a bail hearing for the offender, James Gargasoulas, six days before he rammed pedestrians.
The detective had interviewed Gargasoulas at St Kilda police station after his arrest for threatening to kill a family member with a knife.
The offender admitted to serious crimes and the detective was typing up new charges against him as they awaited a bail justice.
However, Det Sen Const Gentner said he "literally ran down the stairs" to intervene in the hearing when it looked like Gargasoulas would get bail.
Aine Magee QC, representing families of the six victims killed, asked why he did not ask for the hearing to be delayed for 15 minutes so the bail justice had all charges, including the new ones.
"I believe I gave evidence to the bail justice as to what the serious charges were. I don't see how that changes anything," he replied.
The detective said while Gargasoulas was a risk of reoffending, at that stage he wasn't considered "overly dangerous".
But by the morning of the massacre six days later, he had engaged in a series of bizarre and violent acts and critically stabbed his brother.
Police tailed him across several suburbs and Det Sen Const Gentner followed, trying to negotiate Gargasoulas to surrender through phone calls and texts.
"Do you accept you lost control of the situation?" Ms Magee asked him.
"It's a difficult question to answer," Det Sen Const Gentner replied.
"If you look at the net result, I would've certainly hoped to have prevented what occurred down the track."
The detective was texting and calling Gargsoulas to give himself up, at one point texting: "Please don't do this".
He rejected suggestions the increasingly erratic offender was in control and "playing" him.
"I certainly had a strong belief he may come in and surrender," he said.
"He was giving me a commitment he was going to come in."
Det Sen Const Gentner said when Gargasoulas arrived at the Flinders Street intersection in the CBD doing burnouts, there was no indication he'd attack anyone and ramming his car was a risky tactic in a crowded area.
In hindsight, he said if the event was to occur again, he would seek further support of the Special Operations Group - specialists in large, dynamic and serious arrests - and surveillance and the air wing as early as possible.
He understood those resources were requested but not supplied.
Australian Associated Press