The last line of chapter 3 reads:

Tonight, this is their home.

Tomorrow? Who can say anything about tomorrow?

These two lines are closely related to the theme of the impossibility of not living in the present when one knows nothing about him/herself and is in danger. Ship of Theseus is at a very tense moment where S. and his new friends are being persecuted for a crime they did not commit. At the same time, Jen and Eric’s storyline is also at a climax. Eric is planning on going to Dejardins’ funeral and Jen becomes preoccupied:

Eric, stop. You have no idea what’s really going on here. With Desjardins, with Serin, with any of it.

(…)

I’m really, really worried about this. Don’t go.

Eric goes anyway and in the last round of notes he comes back to this page and answers to Jen’s last two notes:

I love that you kept writing.

What else was I going to do?

This shows how by Jen’s second round of notes she already feels uncomfortable in Eric’s absence. He and the book have become her main concerns and what she most cares about.