Ippolit suddenly jumps up, all stressed that he has slept through something. He pulls a giant sheaf of papers out of his pocket and declares that he is going to read a long article that he has written. Everyone at the party is all, dude, that's lame, but he can't be stopped.
Myshkin realizes that he's about to embarrass himself more, and tries to hustle him off to bed, or at least to wait and read the thing tomorrow, but it's no use.
Finally, Ippolit demands a coin toss to see if he'll read. Coin toss says yes.
Rogozhin cryptically says that Ippolit is handling it all wrong. Is this because he knows what the article says? We don't know, but Ippolit suddenly accuses Rogozhin of having come to his bedside in the middle of night to watch him and terrify him. Rogozhin is like, no way dude, but if we're still working with the whole Rogozhin-as-the-devil-to-Myshkin's-Jesus thing, then maybe this is some part of that? It's unclear.
Ippolit starts reading "My Necessary Explanation," which is rambling, doesn't have much of a logical flow, and goes on for several chapters.
In the section that comprises the rest of this chapter, we find these sections:
(1) Ippolit is really, really scared of dying. He's still putting on his nihilist who-cares attitude, but he was totally thrown by the offhanded way a nihilist doctor told him he had at most a month left. He's nineteen years old. That's a pretty hardcore thing to be dealing with at nineteen.
(2) He is struck by how perceptive and on the ball Myshkin is about a lot of things.
(3) He had a really awful nightmare about being attacked by a horrible scorpion-monster thing in his bedroom. In the dream, his mom called in his actually-dead dog to kill this reptilian thing, and it bites the dog while the dog is biting it.
Here, Ippolit stops and kind of freaks out from embarrassment a little bit. Everyone tries to get him to stop reading, but no, he goes on throughout the final sections of the chapter:
(4) Ippolit tries to figure out the point of living for two weeks. On the one hand, why not just die now and get it over with? But on the other hand, he feels like it's actually only now that he has a death sentence of sorts that he has really started to live. (Which, okay, guys, remember the story Myshkin told about the condemned man and how full of life his last few hours must be? This is definitely more of the idea that the person who knows he is about to die lives a very full life at the end—as Dostoevsky himself experience at his staged execution.)
(5) Ippolit is furious at the people he sees around him, each living life and having a lot of life to live. How could they be complaining about anything? If only he could have the rest of his life in front of him, then he'd really show everyone.