Can you survive if your throat is severed??

No it is not gonna happen. Not bone to bone laceration. Not even if it were to happen in the OR with surgeons standing by. Airway isn't the problem. You could conceivably insert a temporary airway while connecting the vessels, providing the patient didn't drown first, but with both external carotid arteries and jugular veins severed, you don't have minutes... we are talking seconds! Get the body bag and a few mops!