The Snare by Rafael Sabatini

Miss Armytage's own notions of what might be fit and proper for her virginal ears were by no means coincident with Lady O'Moy's. Thus, although you have seen her pass into the private quarters of the adjutant's establishment, and although, in fact, she did withdraw to her own room, she found it impossible to abide there a prey to doubt and misgivings as to what Dick Butler might have done - doubt and misgivings, be it understood, entertained purely on Una's account and not at all on Dick's.

By the corridor spanning the archway on the southern side of the quadrangle, and serving as a connecting bridge between the adjutant's private and official quarters, Miss Armytage took her way to Sir Terence's work-room, knowing that she would find Captain Tremayne there, and assuming that he would be alone.