Excuse the massive photos from this camera but you'll probably understand when you look at them.
The actual part (M16086) that catches the mag and the metal rod shaped part which the mag release button screws onto falls apart into two pieces. It seems that the catch and the rod are two pieces probably pressed together in the factory and meant to stay together. In this case they simply slide apart causing the entire unit to fall to pieces on the ground.
http://img291.imageshack.us/img291/9751/0000206fm8.jpg
