Kira's blade comes out and she backs up a step. The fact that Lydia knows where the hideout is notwithstanding, there's only one way to know for sure if this is actually Lydia.]

If you're really Lydia - my Lydia - I mean, the Lydia I know, then Allison would have showed you something, and you would know to show it to me.

[She dips the edge of her blade briefly.]

There, on the ground. Show me.

[If Lydia was vetted by Allison, she'll know the draw the triskellion in the dirt.]