Quote 4
[Raskolnikov:] "I […] hinted that an 'extraordinary' man has the right […] an inner right to decide in his own conscience to overstep...certain obstacles, and only in case it is essential for the practical fulfillment of his idea (sometimes, perhaps, of benefit to the whole of humanity)." (3.5.101)
This is a more complicated-sounding version of what Raskolnikov hears the student say in the quote above from 1.6.14. This is when he's trying to explain his article on the matter to Porfiry. Knowing that he wrote an essay about this business helps us understand just how obsessed he really is with the idea.
Quote 5
[Raskolnikov:] "Surely it isn't beginning already! Surely it isn't my punishment coming upon me? It is!" (2.1.17)
This is just after the murder, when Raskolnikov is obsessing over possible evidence of his crime. The phrasing "coming upon me" suggests two interpretations of the passage: 1) that the beginning phase of Raskolnikov's punishment is being meted out by a force of justice, perhaps God and 2) that Raskolnikov is personifying punishment as a force of justice in and of itself.
Quote 6
[Raskolnikov:] "For one [Dounia] loves, for one she adores, she will sell herself!" (1.4.5)
Here, Raskolnikov is referring to Dounia, but he underestimates her. Although Dounia does think Luzhin can help Raskolnikov, once she knows what Luzhin's true intentions are, she calls it off. Raskolnikov's love for her certainly makes this easier.