[ThaVirus]

Originally Posted by Brando

Spoiler!

Read over on Reddit that the Starks use lead coffins to keep the dead from raising. Wonder if she went down to the crypts to escape and encountered a reanimated headless Ned.

Spoiler!

In the books they laid iron swords over them to keep their vengeful spirits from rising. Old Nan says the Others hate iron and in the prologue the only thing left after the wild long massacre was an iron axe..

So you may be right. It could be reanimated Starks (maybe this is how we'll end up with Lady Stoneheart), ice spiders or just the Walkers themselves. Arya's been through some shit but she's seen nothing like the undead army.

I'm guessing the White Walkers somehow break through Winterfell's defenses and take the castle, leading what's left of the cast to have to escape through the crypts, burning Winterfell in the process.