The City of Ember: Chapter 7

In chapter seven, A Message Full of Holes, Lina decides to try to figure out the message Poppy had in her mouth. Because Poppy was eating it, it was pretty much ruined... but there was still a few words, so it was possible to make it out. She found a couple of words, many of which had to do with the pipeworks, but the rest wasn't so easy.

QUESTIONS: What do you think the letter's about? Will it help Ember be saved? Is it an escape? Do you think Doon will be involved?