There is a possible, relatively innocent, explanation of why Berger stuffed his notes in his pants or jacket. I have been to lots of classified meeting (work as a DOD contractor) and have taken notes. The usual procedure is to hand in your notes to the security officer on the way out. He reviews them and classifies them, if appropriate. If the notes contain secret material, they are made into a new secret document with a sequence number and scary red cover. If, as I often do, you have “mentally redacted” the secret stuff while you were writing, the notes are unclassified. For example, someone in the meeting says, “Our agent in Beirut, Ahmed bin Adhem Finster, informed us of the pending attack”. You write: “An agent informed us of the attack” – that wouldn’t be classified. If you wrote the guy’s name, or perhaps even just the location, it would be.
OK, back to Berger. He may have mentally redacted the notes, and said to himself “Dammit, I used to be NSA; I know there’s nothing classified in these notes, and I don’t want to wait a week while somebody reviews them. I’ll just smuggle them out right now.” Definitely against rules, but not sinister. On the other hand, it’s very hard to see how he could have “inadvertently” removed the classified documents themselves. You’d get shot for that where I work.