What happens if Russia's muslims start becoming radicalized?
"Russia is becoming increasingly a Muslim country. Out of a total population of over 146 million (including two million in annexed Crimea), it counts about 15 million people of Muslim background—even if not all are believers and even fewer practice Islam. Given forthcoming demographic changes, by around 2050 Muslims will represent between one third (according to the most conservative estimates) and one half (according to the most ‘alarmist’ assessments) of the Russian population."
https://jamestown.org/program/marlene-laruelle-how-islam-will-change-russia/
What happens if Russia’s muslims start becoming radicalized?==
Very simple. FSB will find them and send to prison for many years where they will work building some infrastructure projects: roads, bridges etc. If they give armed resistance then FSB antiterrorist team will just kill them using overwhelm firepower.