If Bettiol is in the first group and Carthy in the second then I don't think they'll necessarily pull Bettiol back to help him, even more so if Carthy has riders like Carr and Guerreiro with him who should be capable of doing well in this terrain. If there are other GC riders with Bettiol, then he has an excuse to not work and actually get an even better chance to win. EF like to give their riders an opportunity to follow their individual goals if they have good enough legs.Yes, that's what I thought, too. If someone like Bernal goes and Carthy can't follow anyway, fine, then Bettiol could follow. But he surely won't be allowed to attack and drag other GC contenders with him when Carthy can't follow him. And if they go and Carthy can't follow immediately it's probably Bettiol's task to keep him as close as possible. So unless Carthy cracks or crashes early... I don't see it.
Of course it's possible the situation will get so precarious for Hugh that Bettiol will have to work for him but that's not the only possible scenario IMO.