It works! The thought stopping of inner critic works! It was enough to read about it in the book and pay more attention to the now consolidated concept of the inner critic. I notice when it's about to speak (basically it's any time I feel bad mood suddenly approaching) and then I just decide not to listen to it and next immediately shut it down. Then I keep my attention on the bright reality in a playful way, which helps me not to slide back to the critic, which often doubles its attacks after having been shut down. I believe that my improv experience has a big play in being able to ignore the critic for a brief moment so that I can shut it down. The playfulness may also come from there.
This moment of shutting the critic down feels like forcing and invokes a short feeling of nausea. And that feeling of nausea reminded me of something. One of the adventures I experienced in my life was being prescribed far too many psychoactive drugs due to an emotional breakdown. During the first day of being on those drugs I have noticed that whenever I tried to think something negative about myself I had a strong feeling of wanting to vomit. It was so persistent that I was not able to have a negative thought or I would puke. I was amazed at the power of thought controlling of those drugs. I never had it again with regular SSRI.
But the conclusion is the same - it was the pharmaceutically forced thought stopping!
I wonder what is with the outer critic in such situation. It seems to be a rule that when inner critic grows smaller, the outer critic tries to grow bigger. Indeed I noticed it on myself, and now I need to keep an eye on that too, or else I would become a bitter person, disappointed with the world. But this phenomenon could mean that for people with narcissistic tendencies certain drugs could make their outer critic even bigger, and as the result increase their narcissism. That matches a bit with something I heard from Sam Vaknin about certain medication making the narcissist's condition worse.