Cook rice according to package directions. Meanwhile, preheat oven to 375°., In a large bowl, combine the crab, shrimp, celery, onion, green pepper, mushrooms and pimientos. In a small bowl, whisk mayonnaise, milk, pepper and Worcestershire sauce; stir into seafood mixture. Stir in rice., Transfer to a greased 13x9-in. baking dish. Sprinkle with the dry bread crumbs. Bake, uncovered, until bubbly, 40-50 minutes.