Yeah, that doesnt make sense for me either. I mean even a small amount would kill someone constantly around him. And when he goes Worldbreaker....
However, obviously gamma energy in comics works nothing like it really does. And since writers can't just retcon the gamma dose, they have recently went with the retcon that gamma is tied to basically a magical big green fart cloud lol. I mean.... I guess its something. Now that its magic, at least we can't ask why it didnt kill a ton of people.
And like even if Rick Jones was behind some rock, hed still die from radiation poisoning or cancer.