The Doctor could feel the other Gallifreyan moving closer long before he saw her, and he had started moving as well. To him, the woman couldn't have been more obvious if she had a large flashing sign over her head saying what she was.
The only problem was that he didn't know who she was. Ah, the down side of regenerating.
His eyes narrowed at her and he pulled off his glasses, sliding them, conveniently, into the same pocket that held his sonic screwdriver. He was supposed to be the only Gallifreyan left in time. He'd seen his world destroyed and watched The Master burn, and in all of his time since either of those events he had never even sensed the presence of another.
"I'm The Doctor," he said, his own words short, eyes remaining locked on the woman in front of him. "Who are you?"