The example you quote is (bar one) people moving as pedestrians rather than with the protection of a vehicle. A vehicle offers a great deal of protection, particularly now with air-conditioning available to give a buffer against the heat. Also a slow moving vehicle moves a lot faster (away from danger) than a fast moving pedestrian. I remember a film, probably made in the 1950's (one of those Magnesium Chloride in your everyday life type thing) about "Always stay in the car in a bushfire, cover yourself with blankets and then put out the fires on the car when the fire has past". If you are out of a vehicle in a bushfire you need to dress appropriately to deal with the radiant heat, long trousers, long sleeves, hat etc. As bushfires are associated with hot weather, sadly, people particularly children are made much more vulnerable by wearing bathers (swimming trunks) and short sleeves when moving. Firefighters cover up with clothing for to deal with the radiant heat, among other things.
Can I please point out that the radiated heat from a fire will indeed kill the shit out of you even with your air-conditioner running. If you're within safe evacuation times, the car is a good bet, but if you're past the safe evacuation time you'd have better chances by staying put and making do with what you have.
Being trapped in a firestorm is a terrifying experience, it sounds like it's a damn good thing your uncle had the sense to find a safe place to take shelter!
He was based at the Fiskville training facility for a few years which would have been around that time and explain how he was at Macedon; prior to that he was a station chief so quite experienced.
The way he described the houses around them imploding and how the fire would rush out, take something and then suck back into itself sounded like a nightmare.
It was enough for him to have left the CFA a few years later.
