Toss the scallops with the ginger, red pepper flakes, seafood seasoning, fish sauce, and 1 tablespoon of cornstarch in a bowl. Cover, and marinate 30 minutes.
Heat half of the oil in a wok over high heat. Stir in the garlic, and cook until it begins to brown, about 30 seconds. Stir in the marinated scallops, and cook until they are no longer translucent in the center, about 3 minutes. Dissolve the remaining 1 tablespoon of cornstarch in the chicken broth. Pour into the wok, and stir until thickened. Remove to a bowl.
Clean the wok well, and heat the remaining oil over high heat; stir in the onion, mushrooms, zucchini, yellow squash, and carrot. Cook and stir until the vegetables are tender, about 5 minutes. Stir in the shrimp, green pepper, and scallop mixture. Stir until hot.