At episode 5x10, after Jaqen kills himself, Arya starts removing faces from him until she finds her own. Can you please explain me what this means? How did they get her face?
The Faceless Men obviously have access to some kind of magic:
- When they wear a face their physique/body and voice changes as well.
- They can preserve the faces in the hall without rot.
With that in mind it is easy to assume that a fully trained Faceless Man could have a stronger connection to the magic and be able to use faces of those that are still alive. As @Skooba puts it so well on his answer to a related question on MTVSE I'll quote some of it here:
Jaqen seems to be the leader of the group. This would imply he has a greater or direct interaction with the many faced (similar to how R'hollor will "speak" through the Red Priests). While the extent of this is not fully defined, I believe this example proves this point.
We could also speculate that because of this it appears he may even be able to use any face he wants and not just those of the dead.
A few other speculations as to how it worked:
- Arya was "drugged" and so it was actually just an hallucination.
- When Arya joined the Faceless Men, even though not one of them yet, she donated her face, though subconsciously. This can also explain why The Waif appears to have Jaqen's face on underneath in the same scene. So any Faceless Man's, recruit or otherwise, face is available to all.
As for what it means, well that's opinion based:
- She's been accepted into the Faceless Men.
- She's been offered up to the Many Faced God.
Overall you're not supposed to question the How's and the Why's... It's magic.