Answering the questions as you request means I would have to believe that a mafia head who admits to hating Putin's law and order reform, was later proved to be sending funds to chechen terrorists, funded a movie claiming that the Russian government blew up apartments to win support for a war and this movie was not about trying to discredit Putin.
Then I would have to somehow stretch into believing that a people notorious for blowing things up and stupidly demonizing themselves in the eyes of the world, were not behind the bombings in Russia claimed by Putin to be terrorist.
So after the aliens come down and kidnap me for a visit to another planet, maybe those things might appear reasonable. I'll get back to you.
Berezovsky didn't invent the events surrounding the Ryazan bombing incident. I realise that Berezovsky has ulterior motives to accuse the FSB of being involved in the Moscow bombings. However, the facts surrounding the 'exercise' at Ryazan are suspicious even without Berezovsky highlighting them.