How did Arya Stark escape the Frey House?

Question

Arya Stark killed Walder Frey and then impersonated him to kill his sons.

After the Deadly Feast, she pulls off her mask and tells Frey's wife,

When people ask what happened here, tell them the North remembers. Tell them Winter came for House Frey.

Then she walks out and nobody stops her.

Wouldn't the castle guards rush in to capture her? None of the handful of women standing around the feast hall rushed out to call for guards.

Wouldn't she have to get past dozens of guards? Guards at the entrance to the feast fall. Guards at the castle door. Guards at the castle walls and castle gate. Guards in the field. How could she get more than a mile without guards chasing after her?

How did she escape?

Answer 1

Apart from the handful of female servants, who we have seen be mistreated by the Freys, all witnesses died of poisoning. The guards do not know they need to chase anyone and we do not see any of the servants move to alert them.

Even if the guards were alerted, Arya has faces, including the one she used to get close to Walder Frey in the first place. The Freys and their soldiers are routinely shown as being highly incompetent, so it does not seem likely that Arya would have trouble outsmarting them.

Having said all that, we don't really know how she got out as it wasn't shown. We just know she did escape. Perhaps she simply walked out with her own face and wasn't challenged.