Character mistake: Carrie is back at CIA for a 6 pm brief. She takes a seat waiting to be called. She puts her purse under her chair. Shortly, her patience runs out and she says she is going to bathroom. She tries to enter the briefing and David escorts her out. She immediately enters the elevator and leaves. Her purse is still under the chair in the waiting room - presumably with her car keys, wallet etc.
Character mistake: Carrie tells Aayan that she can arrange for him to study at the Royal College of Physicians. The college isn't a medical school; it's a professional body.
Chosen answer: Everyone else calls him Brody or Sgt. Brody, and it probably became habit to her.
The_Iceman
Can't get the source but I read that even the Producer responded to that. Stating that it was common practise for a military wife living in a military complex as everybody refers to their husband by their last name.