After reading as a reader, I found that the stakes really need to be ramped up early on in the book, so I added a new section, where the threat is introduced and emphasised earlier. This means that I'm going to have to re-work several later sections, but overall I think it's going to work out. I'll make this version VIIIa.
I also noticed some area where the POV is off. I want both voices to be really distinct. I hate reading a book where it's clear from the font or the chapter heading or whatever that the POV has changed, but halfway down the page you forget which POV you're in because they all sound the same.