| Quote #4 [. . .] a black hole, |
These lines finally reveal the sad ending to the memory that has been causing all this trouble. These lines are huge, because they confirm that the girl from so long ago is actually dead, and has been for a while. Now we know why the speaker is so obsessed, and why he can't get back to his lost love.
| Quote #5 nothing happens, you're quiet, you blink, |
The speaker ponders all the possibilities for what death is: is it a quiet passage into nothingness, or a painful, noisy, horrible end? He really works through the options, too, and the noisy ones are kind of scary.
| Quote #6 and your final expression, a hard mask |
These lines give us the impression that all of life is just a long, drawn-out death. Oh, joy.