Who did not see this train-wreck coming. It was pretty clear from watching this wipe on msdnc that he is a loose cannon. I wonder why Current thought for a second that more people would want to watch Keith Olbermann?
1.(nautical) a cannon that breaks loose during battle or a storm and causes serious damage to the ship and its crew
2.(idiomatic, by extension) an uncontrolled or unpredictable person who causes damage to their own faction, political party etc.
"Keith Olbermann is considered a loose cannon due to his volatile personality and track record of demonstrating a lack of ability to maintain composure."
1.(idiomatic) To behave in a way such as to cause damage to ones own faction, political party etc.
"Keith Olbermann's loose cannoning triggered a volley of faithfully quoted media coverage which blasted a hole in his company's profits."