Yeah, the mechanics of the castle have been a little under-utilised so far. You would think that at some point one of the kids would stay too long by accident or a group would decide to try it out, but they’ve been awfully obedient so far 
It was pretty short, but because most of it was Ureshino telling the others about what had happened (quoting other people, etc) I did find it a bit harder to figure out who was doing what in some of the sentences, so I hope no one minds if I run a few sentences by you to check whether I understood them correctly. I’m not going to copy all the text (I’m typing by hand, so any typos are probably mine), so this is just a question to the others who just read this section if my interpretation lines up with what they remember.
page 274
This is the part where Ureshino is talking about how he was treating his friends to snacks (何回か奢ったりしたんだよね). He’s then saying that they started to respect him (僕のこと尊敬してたり) and wanted to curry his favour (僕の機嫌取ったり) (or at least, that’s what he thinks). So 僕の機嫌取ったり means that they were currying his favor and not the other way around, right? (Although in actuality it is the other way around).
And then the next sentence is: それ、もちろんやらされてたわけじゃないよ？ I think that he is saying something along the lines of “of course, it’s not like I was being forced to do it”.
page 278
This is where Ureshino tells about when he went back to school. I think he is talking a bit in a run-on way here, so it was a bit hard to follow.
I think he is saying first (the bit that starts with 自分たちのせいで、僕が学校に来なくなったんじゃないかって) that he heard from the homeroom teacher that the kids at school were worried that Ureshino was staying away from school because of them. But then when he is at school, the kids don’t seem remorseful at all (反省してる様子なんかちっともなくて). He thinks that they are frustrated with him because of the stuff that his parents had said (to their parents) (パパたちがいろいろ言ったかもしれないけど) so he (Ureshino) apologised to them (ごめんって => he’s quoting himself here, I think). And then Masamune says that Ureshino isn’t the one who needed to apologise (お前、謝る必要ないと思うけど). Does that sound about right?
page 279
This is where Ureshino describes the fight. He says that the other kids said that Ureshino had no use anymore if he didn’t treat them to snacks anymore and they laugh.
Ureshino then says: さすがに、それは頭に来るでしょ。
I think this is Ureshino saying “something like that drives you mad, right?” (because it is phrased as a question).
Then he says: キレて、殴ったら、やり返された
I think this is Ureshino saying that he got mad (キレて) and threw a punch (殴ったり) and got the same in return (やり返された).
Does this all make sense? With the lack of pronouns, it is all a bit hard to determine who is doing what to whom… 
And then in the next paragraph he says 先に手を出したのは、僕だからってことになってるみたい which I think is basically saying that he started it, so the whole thing was caused by him.
This is probably also why he said earlier that it wasn’t いじめ?
(page 272: 僕、別にいじめに遭ってるとか、そういうわけじゃないから)
He feels that he brought this upon himself, so he doesn’t want to think of it as bullying?
Poor Ureshino. He really has trouble reading people 
I also had one sentence earlier in this week’s section that I have a question about:
p. 270: こころにはなかなか直線できなかった
The full sentence is:
一気に明るくなったスバルの髪の毛の根元が少し黒くなり始めているのもますます違和感に拍車をかけていて、こころにはなかなか直線できなかった
I think the first part is about how Masamune is uncomfortable about Subaru’s hair. Is the last part expressing that this was hard for Kokoro to look at? I was having some trouble figuring out which part of the sentence applies to which character.
. Or does ちょっと fulfil the same role?)