I'm a geologist, and have worked with radioactive materials for longer than you have been alive in all probability. You only worry about rapidly decaying isotopes.
So everyone else is wrong or lying?
To be honest I was shocked to learn that so little time was required.
And as I said,dont drink or eat anything in the area until you're clear of the fall out.
Seriously do some research and come back and tell me where these people are wrong.
It's an important issue to me and mine since we live in a certain fallout path.