If you are concerned about the other eggs, then I would move the double yolkers to a separate incubator, just to be safe. Though, with so few days left before hatching and both embryos still left alive, I wouldn't be overly concerned about the eggs becoming rotten and exploding.
I definitely would not kill the double yolker embryos at this point, in the interest of both ethics and curiosity. People have had them successfully hatch before; not all double yolker incubations end in disaster. Do keep in mind that there is a chance that not all the chicks will survive, as hatching double yolkers is risky, but at least give them a chance to hatch.
Please keep us updated and good luck with your hatching! It is rare to see double yolkers make it this far and it would be interesting to see if they manage to hatch and thrive.