True; as people begin to lecture and /or discuss things they are passionate about, they tend to not only raise their voice and enlighten their facial expressions, but rather, they also cannot seem to stand still. Think of it as a preacher giving his sermon; once he gets going, he won't stay in one place.
Yes, The murder that escaped from prison was killed by falling and breaking his neck when being chased by the Hound. The main villain set the Hound on the murderer thinking he was Sir Henry, (the main victim.)
It tells us that he is depressed and doesn't really know what he likes. He is immature, and seems to like to argue. He can't see the good in anything and Phoebe then calls him out on it. Hope this helps!:)