Setting of 7th Tower and comparison to our society

So I went ahead and started 7th Tower, and I'm finding the social casting extremely interesting. You're born into a color casting of sorts, Red being the lowest and Violet being the highest. The higher you are, the better jobs, income, and standard of living you have. However, you all live in the same tower. This gives a clear structure to life, and makes some have great standards of living, while others don't so much. The lower the color casting, the more people in it.

I thought about this, and you can connect this social structure to medieval times. The Peasants would be like the lower colors, and given the more mundane work and  the nobility/kings would be the high colors, with a higher standard of living. They all would have to live near eachother in the same castle/land area. And untold danger is outside of this castle, like how there is danger outside of the tower in the 7th Tower. I found this connection from medieval life to this book extremely interesting. I wonder what other connections there will be from our world to this one?

The end...(SPOILERS FOR ALLIGENCE!)

So I've made it to the end of Allegiance over winter break, and I can't say I'm happy with the ending. At all. When Tris was killed, she didn't even try to get back up. She'd been though so much, and it wasn't like her at all to just give up.

I would discribe Tris as an extremely independent person, who goes by her own flow, and isn't afraid to stand for what she believed in. Yeah, all of the death around her was painful, but she always overcame. She didn't take "no" for an answer,  as she's very headstrong. So the fact that she just decides to not even get revenge for getting sucker shot, and just "I FELL INTO MY MOM'S ARMS WHOOP-DIE-DO!" And she just left Tobias behind. She just left him there to hold her dead body! Did she not even care about him? She made very clear signs that she did, so when she didn't even try to come back to life, it made me question that. Knowing the fact that she didn't take "no" for an answer, she would always fight to the end, she just..gave up! Either her character changed in a heartbeat or that was written completely out of character. If it's the former.. I can't say I like Tris anymore. She'd be a pushover, and that's almost devolving as a character.

Overall, the book was great, but the end just.. WHY. It's probably the worst ending I've read, no joke. Worse than Mocking Jay, and that's saying something. But that's for another time.

So now that I'm done with that, any book reccomendations? I'm thinking of reading the 7th Tower Series, but I'm open for other suggestions. I typically like Science Fiction and Fantasy if that helps anyone.