BINGO! Col. Broadwell looked extremely stressed and knew she was going down, along with the General. The subtext of her statement IMO was that if Petraeus knew that local militia prisoners were a possible proximate motive for the attacks then Petraeus knew he was a lie about the video to protect both Obama and himself and his wife's job.
IMO, Broadwell had gone batshit after talking to the FBI because when she said “you may not have heard this” and drops the prisoner bomb she obviously knew it was classified AND she was saying this just days after the 3rd debate on October 22 when Romney failed to take Obama down after Obama lied in the 2nd debate and Crowley backed him up.
She looked stressed and sounded worse. The sound of her voice and pattern of speech gave her away. She knew what she was saying. She was nervous.
I don't really care why she made those revelations. Only that she did. :)