I found this biblical allusion and following commentary very interesting and am going to attempt to venture an idea about it. If anybody would like to add, correct, or completely disagree with my musings, I would appreciate it!
On page 411, "Pokler, billeted at a fisherman's cottage, came in from his evening walks behind a fine mask of salt. Lot's wife. What disaster had he dared to look back on? He knew." This passage is alluding to the God's decimation of Sodom and Gomorrah in the Old Testament. Both cities were practicing various acts of sodomy and this enraged God. Therefore, he let Lot and his family (for they weren't part of the sodoming majority) flee from the land before he destroyed it.