How did you get that from what I said?
You could get burned or blown up if you are close, but radiation poisoning causes thyroid cancer. That is what the Chernobyl victims eventually died from.
Click the link I provided above, and browse that site for information about radiation. I am in no way an expert. I would just hate to be caught in an exposure situation knowing that I could have spent $20 bucks to save my life or that of my family.
These pills will be impossible to get as soon as one dirty bomb goes off anywhere in the world.
Yes, you could still die from cancer. Or radiation sickness - which is what most short term survivors would die from. Potassium Iodide works well to prevent thyroid cancer but not the above. The reason you want potassium iodide is that the thyroid is the only organ that will collect and store radioactive material (iodine) - the potassium iodide 'fills' the thyroid so it doesn't store the radioactive stuff.