Quote Originally Posted by Wikipedia Great Borehole article
The deep core-drilled Kola borehole cannot be directly compared with any other borehole in the world. In a deep core borehole, a section of the rock drilled through is recovered from within the hole. It is this recovered drill core, and the information it represents about the rock that it was retrieved from, that is the most important feature of the borehole.
Thanks! So at least some of it is true! But why would they all become believers? Something must have happened...

There was some kind of natural phenomenon as well, like a vision that all of them saw, or something.

Does Russian speaking internet have information about who the scientists were that participated? Perhaps somebody's interviewed them afterwards.

And why did the one person suddenly decide to clear off to Finland? Quite a drastic decision that doesn't make a lot of sense. And what became of this person after he told his story?