I've noticed that flaming barrels and cars on the maps seem to be rigged to blow when someone walks by. Not instantaneously but quick enough that a walking player won't escape the blast radius. All the barrels and car's that I've narrowly escaped can't be just a coincidence. Try it out yourself and get within the vicinity of a flaming explosive, back away, and see if it blows up. Sounds like I'm a raving loon huh.