Continuity mistake: In the late scene where Edmund and Fernand are fighting, Edmund thrusts his sword through Fernand's right side. Later in the death scene, the sword is in Fernand's left side.
Visible crew/equipment: While Edmond is Fighting Fernand in the dining room there is a crew member that is in one of the mirrors for a second.
Answer: I believe it's just because there is a dirty smelly man that she doesn't recognise visiting her ailing grandfather, she just wants to keep an eye on things.