Heat oven to 425°F. In 2-quart saucepan, mix cooking sauce, flour and seafood seasoning with whisk until smooth. Cook over medium heat about 3 minutes, stirring frequently, until thickened. Gently stir in shrimp, fish and vegetables; heat to boiling.
Spoon hot seafood mixture into 9-inch round (2-quart) glass baking dish. Remove pie crust from pouch; unroll crust and place over seafood mixture. Seal edge and flute; cut slits in several places in crust.
Bake 25 to 30 minutes or until crust is golden brown. (After 15 minutes of baking, cover crust edge with strips of foil to prevent excessive browning, if necessary.) Let stand 10 minutes before serving.