Okay, I must admit I couldn’t stop myself, and I have already read up to about 88%. 
I made this thread a little earlier than usual, partly because I wanted somewhere to record my thoughts before I read on.
General thoughts, contain spoilers up to, I don’t know, halfway through the chapter? maybe earlier:
So this chapter is different after all. And the book’s title finally makes sense!
It seems to me like we’re dealing with parallel universes rather than resets, or maybe just all the infinite possibilities in the Narrator’s student life. Infinite they may be, but their differences are not particularly striking. At least in all three we saw in detail, he spends a barren first two years before ending up with Akashi every time.
So now he’s trapped in this universe of infinite possibilities, seeking a way out. Why and how, I have no idea. But each room seems to represent one variation of his life up to now. I found it interesting that he found his underwear in the washing machine instead of the bear. Was this an early sign that all realities are starting to merge?
Time flows strangely in the Tatami Galaxy. He mentions his hair and beard growing, so time must pass normally for him, but food seems unspoiled. Not sure how 魚肉ハンバーグ are stored (maybe they’re frozen?), but the cake at least should have gone stale after a few days. Meanwhile, I’m very curious about that rice cooker that was mentioned last chapter without any explanation. I’m convinced it has something to do with what he’s doing now, but no idea how.
At least I think I have an explanation for the huge swarm of moths. There is one in every one of his rooms, right? So maybe when he finally breaks free, they all escape? An infinite number of moths from an infinite number of rooms. In all chapters, that was the moment his “fate” changed.
Will コロッセオ, whatever it will turn out to be, be the key to his way out? I guess we’ll find out soon.
I found the part about the geological eras hilarious. I need to look up the etymology of 二畳紀 and 三畳紀. I can’t think why the 畳 character is used, but it’s so fitting!
Edit: I had a sudden thought: What about a cat showing him the way out? In two chapters there was an apparently needless scene with a kitten wandering the corridors. He lets the kitten in for a bit, cleans its eyes and lets it out. Might he come across that kitten again? Everyone knows cats are half-magical and can find their way in and out of anything.