[He steps away from the doors, moving over to the console. He can still hear her. But nothing can hurt the TARDIS, and he's older, now. Much older. Charley is from his past. He's not looking back]
You can't alter the future because what happens is always going to happen. You'd create a paradox. I've learned my lesson too many times. Warning me would have done no good. [He knows she probably didn't hear him, because of the TARDIS walls, but he flips a switch and leaves]