Quote 10
"He cried in a whisper at some image, at some vision—he cried out twice, a cry that was no more than a breath:
'The horror! The horror!'" (3.42-43)
Wow. This is not what we want to be whispering on our deathbed. We don't exactly know what Kurtz is seeing, but we know it's not good.
Quote 11
"One evening coming in with a candle I was startled to hear him [Kurtz] say a little tremulously, 'I am lying here in the dark waiting for death.' The light was within a foot of his eyes. I forced myself to murmur, 'Oh, nonsense!' and stood over him as if transfixed." (3.41)
We're pretty sure that this blindness is metaphoric: Kurtz is blinded by the darkness and evil of his soul.
Quote 12
"[…] I heard him mutter, 'Live rightly, die, die…' I listened. There was nothing more. Was he rehearsing some speech in his sleep, or was it a fragment of a phrase from some newspaper article? He had been writing for the papers and meant to do so against, 'for the furthering of my ideas. It's a duty.'" (3.39)
Kurtz just gets crazier and crazier as he dies, sputtering random words like a mid-grade hip-hop artist.