"If you will excuse us?" signifies a polite request for permission to leave or proceed with an action. Lady Mary directs someone to go to Sir Henry's room, indicating her authority or familiarity with the situation. Her instructions also include a caution to call witnesses if weapons are involved, suggesting concern for accountability and safety.

This scene emphasizes formal communication and prudence in potentially dangerous or significant activities. Lady Mary's tone combines courtesy with a sense of command, highlighting the importance of transparency and proper conduct in the circumstances depicted in Dorothy Dunnett's "The Ringed Castle."