It sounds now like Lena and... her aunt, I guess, were planning this in advance. Dark Dream said there was clay in Lena's feathers, so that might have been from setting up the trap in the pit. None of us noticed anything like that when we were leaving the party, so it probably happened shortly after, once she'd left her room.

Though that raises the question of the struggle in her room -- when that occurred and who it was against. [ ... ] I'm not sure how her aunt would have manifested here in the first place, but... maybe if Lena was fighting her for control somehow...?