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. However, God told them not to look back upon the destruction as they were fleeing the land. When they were hurrying away, Lot's wife fell a victim to temptation and snuck a peek back at the cities. The moment she saw them, she was transfigured into a pillar of salt. Therefore, Pokler is stating that he also has made the mistake of looking at something he shouldn't, and he has (figuratively) befallen the same destiny as Lot's wife. However, the book says that Pokler knows what he has looked back upon, but it never specifies. Thus, I can only venture a guess. Since Pokler is brooding about Leni and "reverting... to childhood" (411) in the next paragraph, I think Pokler thinks that his devotion, to the rocket instead of his family, was the mistake. He couldn't part from it, thought he knew he should, and now he is as colorless and emotionless as a pillar of salt.