We went from Getwo unleashing a bunch cursed being using Mahito's powers to a few days later with all of Tokyo infested with curses and seemingly everyone who was about to fight Getwo now being safe and away from the fight? But we don't know how they got away, just that they somehow did.
It also didn't help that Yuki seemingly showed up out of nowhere. I actually thought it was Mei Mei at first because they both have the same hair colour and figure, and both Mei Mei and her brother seemingly vanished form the story as they were about to battle Getwo.
The last few chapters being structured as they have been has just made it confusing to follow, hopefully it should all be explained soon.
Pariston already explained pretty well but for the sake of it:
Brain was the one to fled because he didnt bother to fight Yuki there now that he accomplished his plan if everyone present tried to fight them it would have only lead to their deaths, maybe it was Utahime who saved them with her tecnique or Larue.
We saw both Mei and Ui a few chapters back they're in Kuala Lumpur thanks to Ui Ui's cursed technique since they couldnt beat the curses Brain used against them.
The transitions in this manga arent as detailed as others but still pretty clear ihmo, like that time on Hidden Inventory.