I could be wrong again but I wouldn’t expect any kind of alcohol to explode with a lot of force. Alcohol burns very hot but it doesn’t burn with a lot of force. What was burning under the car could have just been automotive oil or grease. It’s kind of hard to put out an oil fire too.
Just to be clear, e-glycol is the active ingredient in anti-freeze. It is not an alcohol based substance.
As a side note....Pure ethanol (the same alcohol that is in booze) is considered to be close to an undetectable accerlerant as it tends to burn off completely (or evaporate) and not leave any trace elements behind as in the case of petroleum distillates.