If it turns out that was all a ruse and it was fake blood etc, holy fucking shit is that some of the worse writing in a TV show EVER. Ive been hard on D&D lately, but this would be a new low. There is just no way this is the case.
I want to take it at face value (har har) and just think what happened is what they wanted the viewer to believe, she was legit stabbed and now dying in the streets. But the thing that bothers me the most is not showing ANY reconciliation of what happened after she put out the lights and waited in her quarters with needle. Like, literally zero follow through there, all the sudden we see her happily walking about, on the cusp of going back home without a care in the world.
This is problematic. It shows deception (or incompetence) on the part of the writers, which means there is shenanigans going on with the faceless shit. But saying Arya wasnt Arya is fucking stupid, who else was it? The Waif unmasked and established her role as the assassin. No fucking way Jaqen was Arya there, unless like people said he can change his body shape with magic lol.
edit: yea after watching that again, I was wrong, Waif doesnt try to slash throat, it was weird actually as that was her opening attack, and it was like a waist slash? Did it even land? Thats why I was confused, after that she chock-holded her and stabbed her 3 times in the gut and twisted knife, which I guess allowed Arya to heabutt her and jump off. So the attempt wasnt a flub it was more of a narrative for the viewer, showing us her blatant disregard for Jaqens instructions by trying to make her suffer with an inefficient kill.