The police summary of facts told how Murdoch wanted to do something "cool and special" for the event but in hindsight regretted the decision to use the flamethrower.
The home-made flamethrower was mounted on the back of a vehicle and made to look like a Gatling gun.
Using a modified 9kg gas bottle filled with a home-made propellant of kerosene, pegosol and petrol, the flamethrower shot flames four metres high for periods of four to six minutes at a time.
Fire dancers also asked Murdoch for permission to perform with fire poi and fire sticks, which he gave.
Defence lawyer Craig Stevenson says the area was clear of vegetation, had been doused with water beforehand and fire-fighting equipment was on hand including industrial extinguishers.
Judge David Ruth mulled over punishments and considered a financial penalty to "hurt his pocket" while trying to "bring home the stupidity" of what Murdoch had done.
He convicted Murdoch and sentenced him to two concurrent sentences of 200 hours community detention but left him with a warning.
"If you breach this, I will put you in prison. This was a stupid thing to do."
