Has anyone ever sous vide steak, and finished it off on the grill or oven at a later date? I often sous vide my tenderloin roasts then finish them off in the broiler. I ask because I was thinking about cooking one up, refrigerating and giving to a friend, still sealed, to take home and finish off in the oven or on the grill. I would hate to waste food. In theory, I it’s cooked, it would just be cooler in the center.
Kot, SV cooking was developed by restaurant chefs as a technique to safely separate cooking from reheating for service over lengthy periods of time. Steaks, tenderloin roasts, and chicken breasts are among the most frequent menu items used. Thousands here have also done it.
To be safe just cook at the appropriate combination of time and temperature to ensure complete Pasteurization. That means past Rare doneness by cooking at 131F or higher over enough time to achieve temperature equilibrium throughout the roast. Be sure to thoroughly chill the roast in an ice bath for several hours before refrigerating it.
Inform your lucky friend on how to bring the meat up to its cooking temperature and then brown it just before enjoying.
Yep, for steak I’ve been using a propane grill to complete my sear a lot lately - and being a little lazy by cooking multiple steaks in the same ziplock freezer bag (as long as you don’t “stack” them, you’re not increasing the cooking time as the thickness is the same.
Fridge temperature steaks are more forgiving for searing (though some people don’t appreciate a cool centre) 
If you’ve passed the pasteurization point (see timings in the table on Douglas Baldwin’s site):
http://www.douglasbaldwin.com/sous-vide.html#Government_Pasteurization_Tables
…and keep the bag sealed, then your Sous Vide cooked meat can last longer in the fridge than raw or cooked via other methods.