Hermione had become a bit more relaxed about breaking rules since Harry and Ron had saved her from the mountain troll, and she was much nicer for it.
When we first meet Hermione, she is a rigid rule-follower, even when following the rules has consequences. She gets stuck outside the Gryffindor common room after curfew because she is so focused on telling the boys they will get in trouble if they leave. She does not take the time to consider why others might be making certain choices, only whether they obey the rules or not. After she is saved because Harry and Ron break the rules, she is better able to weigh the pros and cons of her own choices and think critically about situations. Hermione grows better equipped to see all her options to solving a problem, even if the best option lies outside the rules.
There won’t be any Hogwarts left to get expelled from! . . . Losing points doesn’t matter anymore, can’t you see? D’you think he’ll leave you and your families alone if Gryffindor wins the House Cup?
When Harry learns Voldemort is the one after the Sorcerer’s Stone, the stakes in his life are radically altered. Ron and Hermione are still worried about their exams and Snape’s threat of expulsion, but Harry sees the bigger picture. If Voldemort were to come back into power, the consequences would be far worse and affect far more people than if Harry were to get caught sneaking around Hogwarts at night. The curfew makes sense in a place like Hogwarts, and it is a good thing that Hermione and Ron are invested in their school-work. However, as Harry points out, those things are outweighed by the gravity of Voldemort’s intentions.
I think he sort of wanted to give me a chance . . . I reckon he had a pretty good idea we were going to try, and instead of stopping us, he just taught us enough to help . . . It’s almost like he thought I had the right to face Voldemort if I could.
After chatting with Dumbledore in the hospital, Harry believes it is Dumbledore who orchestrated their ability to get to the Sorcerer’s Stone at all. Dumbledore explicitly tells all the students that the third-floor corridor is off limits because it is incredibly dangerous. However, Dumbledore also gives Harry the invisibility cloak and returns it after Harry loses it. He teaches Harry about the Mirror of Erised and approves Harry’s place on the Quidditch team. Although it is against the rules for Harry, Ron, and Hermione to go in search of the Stone, Harry believes Dumbledore sets them up to succeed in their search. Dumbledore is the one in charge of setting the rules, but he also sees the value in bending them when needed.