How we cite our quotes: Chapter.Paragraph or Chapter.Section.Paragraph (depends on whether or not the chapter had sections - some did not)
Quote #13
"But what about Sirius Black?" Hermione hissed. "He could be using one of the passages on that map to get into the castle! The teachers have got to know!"
"He can't be getting in through a passage," said Harry quickly. [...]
Harry hesitated. What if Black did know the passage was there? (10.3.85)
The detail of Harry's super quick response to Hermione's super logical objection to the super cool Map (we'll stop now) is really key here. Harry doesn't want Hermione to be right, so he quickly comes up with a whole series of reasons why she's wrong, even as he's hesitating and wondering if she is indeed right. Sometimes the most dangerous lies are the ones we tell ourselves, which is a lesson Harry has to learn in Book 3.