It's unfortunate that we only have one vocabulary for radiation to cover both a 100 uS dose of fallout and a 10 S one. If a quantity of rock drops on someone we have different words like "pebble" and "boulder" that tell us how concerned we should be. I was shocked to learn that "fallout" in the context of a nuclear war could mean something that could cause you to die in hours, not raise your lifetime risk of cancer somewhat.