Thanks to FutureMan for the heads up on this interview.
Make sure you read the whole interview and it's quite good.
Jen: In terms of the finale, I’m guessing that you’re obviously familiar with the pieces that affect your character. But have you seen an entire script to have a sense of how everything falls together?
Cusick: I’ve seen an entire script, minus one scene. And only the actors in that scene have seen that scene. So I have seen the final scene. I was in it, so yeah. So I know roughly what’s going to happen except for one little scene.
Full Interview Here@Washington Post