I always felt that Sandy Burglar was protecting someone and had direct orders to do so no matter what he had to do. Burglar, as NSA Director, knew exactly what he was doing and for whom.
I think it goes much, much higher than Sandy and who/what was protected by the destroyed/missing documents.
A man doesn't do something as careless as that without some sort of impetus/threat.
I don't think that Burglar had anything to do with Able Danger at the time. His timeframe was more after the fact and the cleanup.
If I wrote a book on him, I'd call it "The Happy Sinner".