The high-profile doctor is appearing at a medical disciplinary hearing to explain how two women patients ended up with catastrophic brain injuries.
Dr Teo also defended allegations he acted inappropriately by slapping a patient in an attempt to rouse her in the wake of surgery, contrasting it with Will Smith's notorious slap of Chris Rock at the Oscars.
"I admit I slapped her like this (demonstrated multiple small slaps to the face) as opposed to the Will Smith-type slap," Dr Teo told the hearing on Monday.
"It wakes them up and it wakes them up pretty quickly. And I will continue to do it."
Speaking prior to the Health Care Complaints Commission hearing, the 65-year-old said he hoped the truth would clear him of wrongdoing.
"Tell the truth and the truth will set you free," Dr Teo told reporters.
One of the issues the panel of legal and medical experts is considering is whether the women and their families were adequately informed of the risks of surgery.
Both women had terminal brain tumours and had been given from weeks to months to live.
They were left in essentially vegetative states following the surgeries and died soon after.
"We were told he could give us more time," one of the husbands said, according to court documents.
"There was never any information about not coming out of it.
"We paid $35,000 for my wife to die. I never got to say goodbye."
Dr Teo said he fully accepted the surgery he performed led to the women being "damaged" but denied the outcome was due to negligence or poor surgical technique.
"Normally what I say to patients is 'I can't promise you anything. All I can promise is to do my best. You're just going to have to trust me.'
"I always talk about death as a potential complication."
He added there was "no exact science" when it came to tumour-brain interface.
"It was my hand, my technique, my doing that she didn't wake up," he said.
"Whatever happened, I take full responsibility."
Dr Teo sparred with commission counsel Kate Richardson SC, denying accusations he unnecessarily cut across the brain midline, which had heightened risk to the patient.
"Look - we can resolve this. I did something wrong. Clearly, I damaged this lady," Dr Teo said.
"The point is I made an error. A surgical error. I went too far and I damaged this lady. No one is disputing that."
In one particularly heated exchange, Judge Jennifer Boland stepped in to maintain order.
"With both of you talking over each other it doesn't help us. I appreciate that it's frustrating," Judge Boland said.
Dr Teo has previously testified he doesn't regret the surgeries because he believed at the time they were the best thing for the patients.
Throughout the disciplinary hearing process, Dr Teo has continued to operate on patients under additional oversight imposed by the commission.
Previous hearings have drawn large crowds of supporters for Dr Teo including former Australian cricket captain Steve Waugh and boxer Anthony Mundine.
The inquiry is scheduled to continue until Wednesday.
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