#also ALSO ALSO that when we see petra's corpse in a failed loop

[mishy-mashy]

(small spoiler about the cloak post)

I forgot if it's shown in the memory snow Ova or just in season 1, but Petra can recognize Emilia in her cloak (and unless you were conscious of that, you'd never even realize it happens, I don't even think Emilia really thought much about it) and people have pointed that out as "oh the cloak has flaws" but it's just revealed later (7 or 8th arc I can't quite remember) on that Petra just has Special Eyes™ and can just see through any and all illusions as more come up later and she's essential for dealing with it.

So there was a reason for her recognizing Emilia, that was for shadowed for her nearly 10 years prior

OHHHH

And this shows in the anime too, when Petra turns to Emilia without the cloak on and is like "You're the girl that always came to our morning calisthenics" when Emilia always wore her cloak then. Other than 'cause Subaru said, this is the start of the kids asking Emilia to join them on the dragon carriage

But it's like- so subtle, because then Petra says ", right?" at the end (might be different in other translations, but that's the one I know), as if she's not certain herself, but SHE IS