While Harriet addresses the crowd of curiosity seekers and journalists, the Doctor disappears. Harriet is unsurprised. The Doctor is not a man who suffers fools gladly.
That sentence ought to read: The Doctor is not a man. Full stop.
"He really is an alien?" she asks Major Patel of UNIT. Despite what she's seen, it's hard to believe He looks so human - and that accent!
"Yes, ma'am." He explains what the Doctor has done for Humanity.
"Although we're aliens to him, he cares about us," she marvels.
The following Christmas she discovers that he cares about other aliens, too.