yep - my guess is this isn't Eri "failing" Polero's test, but that Polero got found out by whatever society/body of governance she/the Shinigami normally operate under.
Given Polero also seems to be kneeling with her arms held behind her in that last panel, she's probably getting punished. And since Eri's technically dead already, she is along for the ride as an accomplice, type thing.
So now it's up to Fumi and Kuroe to save 'em!
The flower crowns were cute, though. I'm almost expecting something about those to factor back into the story at some point, given how much focus was on them (and the selfie) at the final bit, there.
Thanks for the TL as always.