I thought this bit was interesting:

And felt a distant, hollow echo of emptiness radiating from where Death waited, washing over Harry's mind and parting around it, like a wave breaking on stone. Harry knew his enemy this time, and his will was steel and all of the light.

"I can already feel the Dementors," said the gravelly voice of the Polyjuiced Quirrell. "I did not expect that, not this soon."

"Think of the stars," Harry said, over a distant rumble of thunder. "Don't allow any anger in you, nothing negative, just think of the stars, what it feels like to forget yourself and fall bodilessly through space. Hold to that thought like an Occlumency barrier across your entire mind. The Dementors will have some trouble reaching past that."

There was silence for a moment, then, "Interesting."