How deep into the classified world have you been?I'm not sure what you're asking. I've read (and written) plenty of highly classified documents, but I doubt you'd find them relevent to this, and most are routine bits of boring paperwork. Aside from military service, I haven't had much of anything to do with the Pentagon, so I missed most of the really exciting Alien Abduction briefings.
How much have you talked to people who were deeper into it?
Huh? This isn't the Black Hole of Calcutta we're talking about.
I guess it's been both my observation and understanding that depending on the quality of the relationship and the context, colleagues sometimes talk about certain levels of "black" things. But at some point, most people who value their retirement and safety clam up even with fairly skillful questioning.
In any case, I trust the people who firmly asserted to me that they had personal knowledge of WWII and later things that would startlingly shock the nation--even the world were they to become known. That some things have remained even unrumored about for several decades.