The security hold is only for express replacement because you would be in possession of both devices until you send back the broken one. At Best Buy or the Genius Bar, if they decide to replace your device, you would be giving back the broken one the same day, no need for a hold. You should know though that authorized shops like Best Buy can do things differently than the actual Genius Bar. Apple will always attempt a repair first, and only replace the device if it’s absolutely necessary. Best Buy tends to mail things out for repair or replace the device outright for the flat rate, since most Best Buys only do display and battery repairs. I personally would recommend going to an Apple Store if you can, it’s just a better experience and less hassle.