I'd like to go back to before the confession even begins.
"Miss Dashwood, for half an hour -- for ten minutes -- I entreat you to stay."
"No, sir," she replied with firmness, "I shall not stay. Your business cannot be with me . The servants, I suppose, forgot to tell you that Mr. Palmer was not in the house."
"Had they told me," he cried with vehemence, "that Mr. Palmer and all his relations were at the devil, it would not have turned me from the door. My business is with you, and only you."
I can only suspect that had Mr. Palmer been at home, the manservant would have been ordered to remove Willoughby from the building post-haste. I'm sure that with the respectful regard Mr. Palmer has for Elinor, his indignation would have been raised by this appallingly rude entrance.