Remember, "dangerous area" is a subjective term. They could have said how many agents were shot in the past year -- except I don't think any agents were shot in that area. It was likely the generality of saying 'dangerous area' that made it inadmissable.
"Not reporting the Shooting" is an administrative error. Committing an administrative error in order to hide a crime is obstruction. Just like speeding is not a criminal offense, but speeding to get away from the scene of the crime is a criminal offense.