Shift (Silo book 2)

1.  Let me guess..Troy and Donald are the same guy in shift (AI says I'm right)
2. First third of the book is kind of boring..I dislike American centric books 
3. References to Wool are of course interesting
4. Shift is a play on Troy's shifts and a shift in perspective 
5. Helen of Troy
6. Use of memory as a theme is quite good
7. The reason people stop taking pills is because they begin to remember, not the other way around
8. Skipped Mission chapters
9. Donald ignored what looked to be an invitation. He ignored the throbbing, the yearning, the v hormonal rush of being near an ex-lover after centuries of need, and searched instead for his wife. 
10. 100 years too late, Athena and Karma Brewer. Anna's non reaction is a bit weird
11. It's a burden to do what is correct, sound and logical.. how much better for us all, if we had people brave enough to do what was right instead. 
12. Interesting maths problem for Solo who's stuck in a saferoom (desperate people trying to get in and kill him / the room keeps him safe): There is a 4 digit code to enter the room. 1218. There are 10,000 possibilities if you include 0000. Every day, the desperate people will try 3 attempts at the code and then get locked out for 24 hours. The boy calculated that if they start at 0000 eventually after 400 odd days they will enter. But he doesn't know if they started at 0000 going in ascending order or 9999 and going downwards, and what system they are using. So he is having a debate about whether to change the code to a number they have already guessed because otherwise he feels like he's just waiting to die and be found... but he can't be sure what to do because it's possible they are guessing random numbers. I'm sure there is an algorithm or optimal formula for which number to change the code to each day to maximise prospects of survival??
13. The devastation of Helen and Mick long passing, and him being deceived and manipulated by Anna who wanted him all to herself
14. It's time for the truth. You're the reason I'm here, aren't you? 
15. A shadow slid across Anna's face
16. The poop corner
17. Interesting but lots of boring chapters (Solo, Mission) - maybe a 3-3.5.5 - I know that's vague.