I posted this elsewhere but will copy
It wasn’t Arya it was Jaqen wearing her face
1. Walked like Jaqen, wore hair parted down the middle, threw the coin with the right hand (Arya is left handed)
2. Was too obvious. Arya would have never asked for a cabin. The money was thrown around too casually, even if she was capable of stealing such a sum.
3. Lingering shot of statue on the bridge, maybe sorry to leave. Arya hasn’t been there that long, doesn’t have a particular fondness for the place. Could have stowed away as a cabin boy too easily
4. Jaqen’s life belongs to her. He promised her 3 lives to take for the Red God. He took 2, then she named him as her 3rd. Instead of dying he bargained and agreed to help her escape but then when he left he gave her the coin and told her to come to Braavos. And he gave her the words Valar Morghulis, all men must die. Knowing what we know about their relationship with death there would have been no bargain really. He believes in death
His life is owed to the Red God. No bargain can change his fate and he knows it. He willingly dies in Arya’s place, wearing her face, to fulfill the contract on his own life. He also was testing the Waif who did not fulfill the contract correctly by doing a belly wound instead of killing quickly. Waif is going to go out before he is gone officially. Scenes from next week show Waif running/ chasing possible real Arya