The Doctor and Clara both like saving things and they are both frustrated. The earth doesnt need their protection since it has its own defenses. Their zeal for glory almost blinded them to the fact the earth was quite capable of taking care of itself thank you. In The Fires of Pompeii (series four) the Doctor saves the family of his look-alike after Donna pleads with him on their behalf. This time the Doctor offers to save the group but is turned down by Clara. Was this Claras decision to make? She was awfully quick to decide the fate of the others without consulting them. The Doctor and Clara are the least effective rescuers of the episode. Danny saves them from the tiger. Maebh saves herself from the wolves. The trees save the earth from the solar flares.