[His hand went to his face, rubbing at his chin as he thought this over feverishly in his head. There were too many realisations going on at once.]

I . . . didn't realize such a thing existed, let alone Dumbledore had it. I mean, the thought alone that I helped to-to-!

[He realised he might sound too excited about that, and he was still unsure of Snape's allegiance and he didn't want to risk his wrath.]

What . . . what an astounding set of circumstances.