Thanks a lot for translating! I'm really enjoying this manga.
No clue if I'm right, but the most reasonable explanation for this to me is that Nike is mentally ill. Battle scenes and characters instantly disolving into goo is completely different from what this manga has been about, so Nike is probably hallucinating it all. It could be a reason she's so quiet and distant, and why Pieta just barged into it with no clue about what's happening.
The way the loop got resolved was confusing and unclear, and I'm not sure if Pieta managed to get over the deep trauma that put her in the loop in the first place. I just blazed through this entire manga today, so I might have more thoughts after I get some sleep.