[gruturo]

Radiation in the red forest is supposedly not terrible _ if you don't disturb the soil _

All the nastier bits are under a layer of "clean" soil and you would have no contact with them ordinarily.

These soldiers actually dug down to the nasty bits and likely breathed some of the dust in.

Between that, and eating wildlife (which acts as a powerful concentrator), I'm not surprised they died. The exposure must have been thousands of times above the already non-insignificant baseline.