2. Stepping Into His Own Time Stream
Without the Doctor, the universe would have been destroyed. We found out in episodes like "The Name of the Doctor" and "Turn Left" that his personal time tunnel runs through crucial moments in the history of the universe, and that without him the stars would go out. The Doctor is essential to the fabric of the universe, because if he hadn't been around to save us the whole thing would have been over, caput, lights out for all creation. So what the hell did he think he was playing at, stepping into his own timestream? He could have imploded the universe, and that's before the paradoxes imploded time! From an objective perspective, he should have just let Clara be dead. She had done what she set out to do, had saved him and through him the universe. She was ready, like Amy, for her story to be done. The fact that the Doctor would go after her, would risk the universe collapsing because there's this girl he loves, is actually a very hopeful one. Because he made the human choice, not the choice of a god. Crazy, but very, very human.