I wonder how much radiation any of them were actually exposed to? It is my understanding that most of the ionizing radiation has dissipated pretty quickly and you only get "exposed" to it at close enough range, which none of them were. The other source of exposure is from the particles that are dispersed but that was probably just about as dangerous for the residents in the unlucky town 50 or 100 miles away who got a rain shower 4 hours later from that cloud it morphed into.

There are people walking all over the Chernobyl area, and as long as they do not get dirt on their skin or inhale it, it is pretty safe. The concentrations are generally worse as one gets close to the ruined reactor, but there are even scientists who work at that reactor a lot. They do get some additional exposure, which probabilistically increases their risk of various cancers in the long-term, but a lot of things are probabilistically associated with increased risk of cancer.

I am no expert on the matter, so I don't want to sound like I'm speaking authoritatively, and I certainly haven't even tried to work it out mathematically . . . but having looked into the topic a bit over the years, that is my gut intuition.

If you are close enough to a conventional (i.e., not "radiation enhanced" bomb that you will suffer from the radiation exposure you are probably being exposed to the blast pretty severely too. Both the radiation released from the detonation and the blast effects drop off rather quickly with distance from the bomb, which you can see in the video. Despite the obviously massive destruction at the distant sight of ground zero (what is that 3 or 4 miles?) the effects at the positions of the soldiers is little more than a strong gust of wind.

ADDIT: here is a link to a section of a longer report that goes into some details on the probably radiation exposure of the inhabitants of Nagasaki at the time it was bombed. Don't see how to copy-past any of it into a quote, but it seems to more or less bear out my skepticism.

https://books.google.com/books?id=RAgAAAAAMBAJ&pg=PA46&lpg=PA46&dq=%22radiation+at+Nagasaki%22&source=bl&ots=_kZarF0ma3&sig=cbShMx7edkubEGWklWinQZAasU8&hl=en&sa=X&ved=0ahUKEwjH5L6H06LKAhUGdD4KHSURDQ4Q6AEILTAD#v=onepage&q&f=true

If you scroll up to "The Cause" and read through that whole page it is kind of eye opening. 39,000 people were within 2000 meters of the "hypocenter" and still alive as of the 1st of October, 1945.

What does seem to have resulted from being that close was an increased risk of leukemia (25 times) and small increase in risk of cancer (1.6 times).

The army at one time tried to develop a low-yield nuclear hand grenade as well. Trouble was, it had a blast radius of over 100 meters, and not even the best soldiers could throw it that far.

Given that the average run of the mill soldier can throw a hand grenade some 30-40 meters, I wonder what made them think, that a grenade with 100 meter blast radius would be a good idea, and a nuclear one at that

Why throw it! Run up on the enemy positions and spike it like a Super Mutant badass!

Hehe, yeah, it should be considered more of a suicide weapon / last resort kinda weapon But there have been a good deal of crazy ideas and inventions during wars, so, shouldn't be surprised I guess