Mistake of the master?

I found this task in Rin Kajho’s book Golden Opportunities. In this task, a plan to destroy the white group is considered. At the center of this plan is the destruction of the white eye at point M1. It was exciting. But the author argued that White would inevitably build his upper eye with a move to point P7. I decided to check whether this is really so and I came to the conclusion that the upper eye can be destroyed by the M7 move. Perhaps I don’t see any kind of white protection that the master knew unconditionally.

Well, ok, I was mistaken, the upper eye is impregnable. There is one dame Q6.