Another line with a complex and foreshadowing double meaning. "In the end,"
Nostromo's undoing is indeed because of darkness: Viola shoots him because it
is literally too dark to identify him. But I also see a symbolic meaning here,
regarding darkness as isolating subjectivity. Nostromo's successful career has
been based on the dream-ideal of reputation: how he is seen subjectively by others.
The darkness was indeed his "protection." But when he steals the silver,
he uses his reputation as a disguise; the same subjective dream-ideal becomes
a cloak for the "undoing" of his integrity.