Better When Broken
Summary: The Doctors mind is an amazing thing, and once it's broken, it might just be too great a challenge for even Jack Harkness to fix it, especially if The Doctor is not too keen on letting him. [Post-Waters Of Mars - Done before? Yes. Done like this? Never.]
Prologue
There are some things that, when broken, don't need to be fixed. Some things are better off that way, shattered into a million pieces. Who would eat an egg without first breaking the shell? What fun were fireworks that didn't explode? Yes, there were many things that were better when broken.
A Time Lords mind, however, is not one of them. That much was made obvious when one merely thought back to the Master, to all he had done and tried to do once the drums had driven him into madness. And yet, as the Doctor watched in irritation as Adelaide Brooks turned from him with something akin to horror in her eyes, he didn't look back, didn't think for one moment that maybe the reason she wasn't smiling, the reason she wasn't thanking him for saving her life was because, in that moment, he had looked just like the master. That, if he had looked in the mirror right then, he would have seen the same crazed smile the master always wore on his own lips. And still, even if he had, would he have cared?
The answer to that was debatable, but really didn't matter, in the end. The 'what ifs' of the situation were useless; all that mattered was that he didn't look back, didn't wait to hear the gunshot before closing the TARDIS door behind himself, didn't realize what he had become. And, as he set the TARDIS whirling into the time vortex and the madness took an even deeper hold on him, he didn't, for the first time since he could remember, care that the future was bending around him in ways that it was never meant to.