During the incident Ms O'Hara suffered a minor injury to her head where Mr Crammond hit her.
Police and ambulance crews arrived to find a wounded Mr Crammond on the toilet.
"Agitated and combative", he was taken to hospital where he was pronounced dead about 8pm from the effects of stab wounds to his torso.
Despite Mr Crammond shouting he did not want to die after he stabbed himself, Mr McElrea ruled the death a suicide.
"The bizarre actions in stabbing himself were intentional and he knew the probable consequences," the corner said.
Like police, he was satisfied nobody else was responsible and ruled the death out as a homicide.
Tests taken from Mr Crammond's body show his blood-alcohol reading was almost twice the adult driving limit, and he had traces of cannabis in his system.
He had no known history of suicidal tendencies but had recently lost his labouring job after testing positive to drugs.
Mr Crammond also had a criminal history and had a police alert on his file warning he was prone to carrying a knife and firearm.
Where to get help
• Lifeline: 0800 543 534
• Suicide Crisis Helpline: 0508 828 865
• Youth services: (06) 3555 906
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (4pm to 6pm weekdays)
• Whatsup: 0800 942 8787 (noon to midnight)
• The Word
• Depression helpline: 0800 111 757 (24-hour service)
• Rainbow Youth: (09) 376 4155
• CASPER Suicide Prevention
If it is an emergency and you feel like you or someone else is at risk, call 111.