That entire episode was one of the most thrilling in the series. I do wonder how all the CG is incorporated so well. The CG TV industry has gotten unbelievably good!
@calabi - thats the major issue with CG is that a lot of cinematographers dont pay attention to what the shot would actually look like in real life and then they ask why it looks like CG.. well lets be honest some really GREAT CG shots could never be filmed in real life so its a two sided coin.