Conversation so far:
how long was Nikolai Yezhov in power before the fall from power?
the possibility that in due course he could be removed from the leadership of the punitive apparatus and replaced by fresh people.
where was he in power / where did he rule?
too much power to be allowed to live.
The defection to Japan of the Far Eastern NKVD chief, Genrikh Lyushkov on June 13, 1938.
how old was he when he fell from power?
June 13, 1938, rightly worried Yezhov, who had protected Lyushkov from the purges and feared he would be blamed.

Question: were people happy that he fell from power?
Self-contained rewrite: were people happy that Nikolai Yezhov fell from power?