I hate the way the Faceless Men story has played out. Arya has all of these skills that she has been taught and developed but everything that led up to this episode flies in the face of what she has been taught.
So She is trained to be a faceless man and to be no one but when she goes to put the poison in the actor's rum, she's noticed by the actor. Secondly, she knows that the waif is looking for her, she knows that she can change her looks, but she just lets that old woman(waif) come right up on her and gets stabbed.
You are assuming that Arya could do things she was not allowed to do…
Arya cannot change her looks the same way that a ‘faceless man’ could.
She was warned that ‘the masks are like poison’ to her…BECAUSE she was NOT a ‘true faceless man’ yet. (Keywords: not yet)
The ONE & ONLY time she ever DID use the masks (before she was ready)… she ‘went blind’ because of it.
Therefore, she cannot use any of the ‘masks’ seen in the House of Black & White to change her appearance, like the Waif could.
- When she puts the poison in the actor’s rum…. Arya IS NOT YET a ‘faceless man’…. that’s WHY she was even noticed leaving. (Because she could not use someone else’s identity to make a ‘clean getaway’.

)
- When the Waif stabs her…. Arya IS NOT YET a ‘faceless man’…. that’s WHY she was able to sneak up on her, completely unnoticed. (i.e. Fully-trained Faceless men NEVER stop being ‘faceless men’… while regular folks DO take a break sometimes, or ‘get caught slipping’…. if they get distracted by a beautiful Sunset & start daydreaming about what they are going to do FIRST... whenever they get back home for the first time in 5 over years


)
During her training, the Faceless Men know everything about her, know where she is at all times, are always watching her, and even can tell when she's lying just by looking at her, but when she doesn't fulfill her obligation to the Faceless Men, Arya just is allowed to dip off to a secret hideaway that no one knows about.
First of all, she doesn’t OWE the Faceless Men anything.
All ‘debts’ are paid directly to the Many-Faced God.
The Faceless Men just ‘manage the books’, so to speak… to ensure the debts are actually paid.
(If you owe a loanshark money... eventually, he will send his 'leg-breakers' to collect.

and that's exactly what the Faceless men are like.... consider them the 'life-snatchers' for the Many-Faced God.

)
So yes, Arya DID fulfill her obligation to the Many-Faced God.
- A ‘jealous actress’ paid for 1 Death. Only.
- So Arya was supposed to deliver 1 death to the Many-Faced God. (i.e. The Lady Crane)
- But Arya gave the Waif’s death to the Many-Faced God instead.
Therefore, Arya doesn’t OWE Jaqen, or the Faceless Men a damn thing.
- Someone paid for 1 ‘orchestrated death’ from the Faceless men… and they got one.

- It just wasn’t the Death they were expecting.

- And at the end of the day…. it does NOT matter to the Many-Faced God. A death is a death.
That’s WHY she is allowed to leave…. without ever needing to look over her shoulder for the rest of her life.
Finally, the waif has kicked Arya's ass in every conceivable way during training and we are just supposed to believe that a wounded Arya is supposed to be able to flex on the waif just because she shut out the light by slicing the candle. Wasn't the waif trained the same way....wouldn't the waif have been trained on how to fight without being able to see?
The Faceless Men was a great story arc in the book. it cemented Arya as my favorite character in the books. They did it no justice in the show.
Not at all.
Think about it…
The Waif was much more ‘disciplined’ than Arya.
So she would never have ‘gone blind’ at any point for disobeying Jaqen.

And there was no evidence on the tv show to suggest that the Waif ‘went blind during her training’ at any point.
Now, we could use YOU as a better example.
Let’s say YOU are a UFC heavyweight fighter, for arguments’ sake

….
Go stand alone in your bathroom…. or in a closet that has zero windows (nor any light of any kind peeking below the doorway)….
Or wait until nighttime, if it helps to achieve 'total darkness' in the room you have chosen……
Now cut the lights off quickly…….
Notice, your pupils need some time to ‘adjust’ to the darkness….
While your pupils are adjusting.... that’s the same time when Arya is ‘poking you’ full of holes with Needle.
Cuz it only takes mere split-seconds.
Then she would just stand still in the corner for a few minutes…. as you bled to death….. while swinging around recklessly in the dark.
Hitting nothing at all.
There’s your answer.
