Those with BPD have trouble regulating their emotions. They have no control over them. Things that make them angry send them into a rage (which is why we hear so much about her violent outbursts), things that make her happy, elevated and things that make her sad send her into despair, thus the dark journal entries and references to suicide. It's probably all she could do to hold it together while the cameras were present, which is why she had to detach by drawing and pretending sheb couldn't hear the person on the stand somtimes. After court is probably when the emotions came out, like when people could hear her yelling after the guilty verdict in another room.
imo.