In a zipper top quart-sized bag, combine the grapefruit juice, soy sauce, honey, ginger, garlic, salt and pepper. Add the filets and seal the bag, then marinate in the refrigerator for about 4 hours.
Preheat the oven to 425°F. Heat an oven proof skillet over medium high heat. Add the oil, and turn the pan so the oil coats the bottom of the pan. Sear the fillets on all sides, about 8 minutes in all, watching to make sure they don’t get too brown from the sugar in the honey.
Transfer the pan to the oven (or if you are making a number of them, you might want to transfer them to a larger baking dish), and roast the filets for about 10 to 15 minutes, until the center reaches 150°F. for rare, 160°F. for medium. Remove the pan from the oven, transfer the filets to a cutting board and let them sit for 10 minutes. Slice them as thinly or thickly as you like.