Sharyn Collis told the royal commission she was receiving electric shock treatment by Dr Selwyn Leeks when she was sexually assaulted by him.
Survivors were given electric shock treatment and subjected to high doses of drugs and sexual abuse.
"Without a mouthguard, a person would end up biting their tongue off."
Age Concern says sadly the woman's case is not the worst they have dealt with.
For Māori, the figures were worse.
The vast majority give up their claims for long-term support because they say the process is too traumatic.
"I can still hear those screams today ... it just showed what a brutal, sadistic person he was."
"He was screaming he was going to kill me."
"We were all screaming, screaming for our lives."