A man wore a homemade explosive vest into Ballarat's St John of God Hospital less than 24 hours before he died in an explosion, a coronial inquest has heard.

The inquest into the death of Glenn Sanders began in Warrnambool on Monday and detailed how he spent much of his final day in Ballarat prior to his fiery death on April 12, 2014.

The court heard that on April 10, Mr Sanders held a friend captive and threatened to kidnap a local child until he got answers as to why people were out to get him.

Clinical psychologist Allen Woodward, who treated Mr Sanders for a short time, said Mr Sanders was suffering from delusional disorder and paranoia.

Following the events of April 10, police swung into action with caution as they were aware of Mr Sanders predilection for explosives. 

On April 11, Mr Sanders left Derrinallum to drive to Ballarat while wearing an improvised explosive device (IED) made out of a woman's bra under his clothes.

A police surveillance team was deployed and followed Mr Sanders as he drove to Sovereign Hill, then a service station.

Mr Sanders then visited his brother before attending St John Of God, where his mother was a patient undergoing treatment for cancer. 

Mr Sanders then went to Bunnings where he bought a timer device and a 10kg container of chlorine before heading home.

The police received information from Mr Sanders' brother indicating that Mr Sanders "was an ice user and his doors were booby-trapped and there were homemade IEDs on the property".

Police decided the best option was to put a safe perimeter around the Sanders’ property and to have him to be asked to show himself and surrender his devices, which kicked off a siege that lasted until 1.20am when a series of explosions occurred, killing Mr Sanders and injuring two police officers.