The one-time accused murderer's voice faltered when he recalled finding his brother Stephen covered in blood and curled up in his bedroom.
In an exclusive interview with the Herald on Sunday later, Bain revealed he still saw a counsellor to deal with his 18-year ordeal.
"When you have lived with an emotional pain, after a time, it's something that is just bearable. You can carry it. It's not actually coping, it's just functioning."
Karam also gave a short address, and was moved to tears after Bain's speech, saying he was just "so proud".
Although he's now trying to live a normal "average" life, Bain said the memories of his dead loved ones continued to haunt him.
"For me it's not a dream, it's a waking nightmare and I've got to voluntarily talk about it.
"Every time I talk to the counsellor, every time I talk to Joe or my lawyers, I have to re-live that nightmare."
Bain's address began with photos from his childhood. He spoke of playgrounds, abseiling, swimming, outdoor activities.
He then described his father as strong, stoic, capable and respected in the community. His mother, he said, was artistic and musical, and when he was 16 and was skinny and had acne, his Mum became his friend and confidante.
He described each of his family members while showing photos of them. When they moved from Papua New Guinea to New Zealand, however, cracks started to show. His father found it difficult to find a job, he didn't like his job. His parents ended up separating and for four years his father lived in a caravan behind the property.
On Sunday, June 19, 1994, the family sat together and watched a movie, ate fish and chips. Estranged sister Laniet was staying for the weekend. He was woken in the night by loud arguments and thinks his mother left for a time but then came back. David did his paper round the next morning.
He came back and saw Mum's light was on, thought she was awake. David went upstairs and found an open packet of bullets in his room and his rifle gone.
David went to his mother's room, saw her propped up on pillows. Then he pulled the curtains back and saw blood streaming down her face and realised she was dead. After that he said he blacked out and has marginal recall. David's voice faltered when he recalled seeing Stephen curled up on the floor.
One of his sisters was bent into an unnatural position. There was blood all over Stephen's room. He felt confused, he was blacking out, couldn't focus and was having random thoughts such as "I need to hang the washing out" and "I need to do my university essay".
The next few days cut him "to the core". He had to undergo a full medical strip search.
Bain's sadness turned to anger when he discussed the way he was treated during his first trial.
"They systematically destroyed my family's and my reputation. Everything I said fell on deaf ears."
He raised his voice, saying "The system had failed me, it had betrayed me", and described the justice system as a "creature without compassion".
In one of the police interviews during his trial, Bain said he was told "either it was your father or it was you". When he finally asked for a lawyer, he was told "Congratulations David, you're now a criminal".
Bain says of his future, "I do hope for as normal a life as I can possibly get. Working, dealing with everyday normal things like paying bills. It's like Joe said, I'm average."
