“killer radiation zone”
This is loose terminology.
Radworker safety incorporates a combination of dosage, time of exposure and shielding.
I can get a “killer” radiation dose by swallowing certain watch dials. OTOH, I can stand a foot away from a spent fuel rod if I have a foot of lead and leaded glass between, without any ill effects whatsoever.
My dad, who was a WWII combat vet in the Med, Battle of Rome, Occupation Forces of Germany, and then to Korea etc. was detailed to the US Ivey series of H-bomb explosion tests. I remember early in my life when he finally came back and bringing all kinds of stuff back, among them were a dozen or more thick black plastic circular disks about he size of 5-7 stacked quarters added to his dog tags.
His medical difficulties didn't manifest themselves early, it took years. Had it not been for my mother getting copies of his orders from others in his unit where his name was also present, we could never have proven his medical disabilities were due to this service. The government fought tooth an nail, but the orders clinched it. They finally granted him full 100% disability in the late 60s. He died in 1971 age 57 while I was overseas. Frankly, I think we all know we aren't talking about watch dials and spent rods here.