A concise answer to the question in the post's title is of course they should.

However, where would half a million Japanese go?

Most of Japan is mountainous and over 80% of Japanese live in cities.

In the mountains there is no infrastructure for 1/2 million Japanese and in the cities there is no spare space.

The alternative is for them to go abroad but I have yet to see other countries offering refuge.

Even if they did, the Japanese are very insular indeed and unlikely to go-even if death results from their actions.

The sad fact is that most of the Japanese with high exposure levels and those that continue to receive high levels means that in the near future, death rates will soar.

I have heard firsthand from a doctor friend that the levels of cancer in Fukui prefecture ( a prefecture with 3-4 reactors) that the cancer rate was double the national average in Japan.

This information is not common knowledge in Japan as the information is snowballed.

It is a tragic situation indeed