Harker vs Muir and the horse story
It's implied (at least to me) that Harker is suspicious of Muir even before the announcement of Bishops imprisonment. So after the announcement is made Harker wants Muir to comment on the record what he thinks about the announcement which could probably implicate Muir as a leak.
Muir pulls out the horse story and suddenly Harker is bored to death just seconds after he was intensely demanding Muir to speak out. Why Harker did not demand Muir to stay and talk about the issue is a continuity error in my opinion.
What do you think?