Just quickly, but here's the line for Turn 21:
TURN21「世界は欺瞞という仮面を脱ぎ捨て、真実をさらけ出す」
"The world shall throw off the mask called deception and reveal the truth."
I think this is roughly accurate, but feel free to correct me if necessary :) Also, (going by memory) the behind-the-scenes section just talked about the decision to have pebbles on the ground and talked a little about episode 17, "The Taste of Soil." Nothing much new there.