HBO Chernobyl makes it very clear that the 3 men survived for many years after the accident and that at the time the show was made 2 were still alive.

https://www.youtube.com/watch?v=OHrVlyU3suk&t=132s

Edit: Everyone at the time probably thought that they were being sent to their deaths so they were staggeringly brave - but that's not how things turned out.

I don't know the show you are talking about:

I am talking about actual voluntary suicide missions in chernobyl, like Lelechenko, Aleksandr Grigoryevich:

"in order to spare his younger colleagues from radiation exposure, he went through radioactive water and debris three times to switch off the electrolyzers and the feed of hydrogen to the generators, then tried to supply voltage to the feedwater pumps. "

And he and others did pretty much die right away.

https://en.wikipedia.org/wiki/Deaths_due_to_the_Chernobyl_di...