In the Dyatlov group there was a real "liquidator" of a nuclear disaster Kystym-57 (the 2nd worst in history https://en.wikipedia.org/wiki/Kyshtym_disaster) https://dyatlovpass.com/yuri-krivonischenko - an engineer at the USSR version of Hanford. Later he tried to resign very disgruntled from his job, and instead they reassigned him to the most polluted site. Given the level of secrecy back then, especially considering that it was a weapon plutonium facility, and what he may have known and what shape his disgruntlement may have taken... so i wouldn't be surprised if the issue was taken care about in this way of "accident" (people were killed for less - for example in 1962 USSR shot a peaceful demonstration of regular workers in Novocherkassk who wanted better living conditions, and that was much less important than anything related to nuclear weapons in those years)