origin stories are very intriguing

Peter Brock was drafted into the Australian Army in 1965 and spent his two years of National Service stationed at the Blamey Barracks near Wagga Wagga in New South Wales. 

During his time in the army, Brock was in the Medical Corps where he often served as an ambulance driver, he and his mates used to race the ambulances around the base. 

It was while on leave from the army in 1966 that Brock first visited Bathurst to watch the 500-mile production car race that was to become the Bathurst 1000. It was after watching the race that he decided that he wanted to become a race driver when he left the army.

https://en.wikipedia.org/wiki/Peter_Brock