Help! what do I do with the aftermath of a tragic accident

If the roast is already cooked, grilled steaks sound like a wonderful way to reheat it. Just a sear on each side and you're good. Also, you could shave it for cheese-steak sandwiches or French dip.

I think it might be a good idea to remove the salt crust, since it will be a few days before you can enjoy it. I'd be afraid the meat would absorb too much salt in the refrigerator. How to reheat it kind of depends on how done it is now, and how well cooked you prefer it to be. The ideal way to reheat it would be to use a sous vide machine, set for the doneness you wanted to achieve- about 130 or so for rare. If your roast was already nearly done, any kind of other cooking method is likely to take you past that ideal rare, and possibly give you dry meat. If you want to use the oven method, you could put it in a pan with any au jus, cover it tightly with foil, and bake it at say, 275F until heated through. If you don't mind losing the appeal of an intact prime rib, you could also simply slice it into steaks, and grill them to a medium rare state. That wouldn't take so long, and the steaks would be wonderful tasting all the same. Personally, I like leftover prime rib at room temperature, sliced thinly. So that might be an option worth considering as well. Remove your salt crust , slice it thin, and store it in any accumulated juices. To serve, heat the juices, toss in the slices to barely warm, and serve that way. Whatever you pick, I'm sure it will taste wonderful. The most important thing in any shared meal is the company, not the main dish, and laughter is a very important seasoning in life. No matter how you opt to reheat and present your roast, if will taste best when shared with friends and family.