| Quote #10
And so [Ivan] was sitting there now, almost aware of being delirious, and, as I have already said, peering persistently at some object on the sofa against the opposite wall. (11.9.1)
The devil appears to Ivan when he's sitting alone in his room. This passage recalls Zosima's definition of hell as the consequence of isolation from the bonds of love that unite humanity (see Quote #6 above).
| Quote #11
There was a note on the table: "I exterminate my life by my own will and liking, so as not to blame anybody." (11.10.1)
Not only does Smerdyakov die alone; his suicide note suggests that he wants to isolate himself from all human consideration, even in death.