Ah. From http://www.fanfiction.net/s/5782108/46/Harry_Potter_and_the_Methods_of_Rationality :

'Hermione had refused to answer any questions, and as soon as they'd passed the split leading to the Slytherin dungeons, Daphne and Tracey had peeled off at once, walking as quickly as they could. Rumor traveled fast in Hogwarts, so they'd have to go to the dungeons right away if they wanted to be the first to tell everyone the story.

...

"Yes," said Pansy sourly, from where she was sitting with Gregory's feet in her lap, leaning back and reading what seemed to be a coloring book, "Millicent already told us."

How -'