When demolition crews finally knocked down the long shuttered Oak Knoll Naval Hospital earlier this year, there was one person who deserved more credit than anyone else for finally ridding Oakland of that dilapidated eyesore. In fact, Don Mitchell, leader of the Sequoyah Hills and Oak Knoll Neighborhood Association, spent much of the past few years helping lessen the immense dangers presented by the former Navy property in the Oakland hills. He went after SunCal, the owner of the land, and its bankrupt ex-financial partner, Lehman Brothers. And his relentless efforts helped prompt then-City Attorney John Russo to file suit to clean up the property, which was choked with toxic asbestos and overgrown vegetation, a fire disaster waiting to happen. He also pointed out that the Oakland Fire Department had worsened potential fire hazards when it cut large holes in the roofs of city-owned buildings on the property for training exercises — a move that would have hastened the spread of fire had a blaze broken out. In short, not much went unnoticed by Mitchell, not even the Oakland zoo employees who secretly, and illegally, cut down trees from public property to feed to the zoo’s elephants and giraffes.