The opening chapter of He Who Fights with Monsters is probably the weakest of the three, it's certainly the slowest but it's done so deliberately to set the Doctor on his journey to seek out and assassinate the Barber Surgeon. It's still a powerful opener, showing just how much damage the Barber Surgeon has wrought on the universe, not just to the Time Lords but Daleks as well and we see how his carnage has affected the Doctor, we also get some evolution of the War Doctor's character showing how weary he's starting to become of all the fighting and how the last remnants of the old Doctor is slipping away. As I said, altogether He Who Fights with Monsters is one of the War Doctor's all time best and I highly recommend it.