It's the Day's Day of Days! Because The House in Turk Street.
As we watch Muir reiterate that he wants absolute licence for he and his, absolute submission from everyone else, let's just consider that last line.
Muir has regularly fantasized about killing those he doesn't like. But that doesn't count. Because he got reminded that he is mortal and bullets don't care about what your politics are, so now he's gonna pearlclutch, try to pretend that it's his opponents who are like that, not him, and in essence, desperately pretend to the moral high ground. Because the civil war and bloody purge weren't supposed to carry the risk of being one of the people getting killed.