Slack interview questions

First, I had 1-2 telephone conversations with the recruiter. Second, phone interview with hiring manager who was very down-to-earth and felt good rapport. Third was in person -- started with warm conversation with hiring manager and recruiter in lobby, then cycled through a number of people on the team and teams in other silos, ending with a peer to the hiring manager. Everyone was fantastic -- up until the last interviewer. She showed up late -- the hiring manager was about to cancel and send me off without seeing her when she rolled in, disheveled and a bit grubby (maybe she had a bicycle flat?). Instead of a warm or courteous greeting, she opted for distance, blocking rapport and establishing domain. She refused to shake hands, moved to the farthest side of the room, forcing me to re-orient to her preferred location (all other interviewers had been sitting across the table corner for discussions). She started off brusquely as follows: "This is going to be an informational interview: that means that I am going to ask you questions and you will respond using examples from your actual experience. If there is enough time at the end, you can ask me questions - is that CLEAR?" I tried to deflect and assured her that was similar to the discussions I had with her colleagues throughout the interview. Her first question: "Tell me about a time when scope changed on a project and how did you handle it." I provided a variety of examples -- without using specific details of the projects, names of companies or other details that would probably violate an NDA, providing different scenarios based on impact of the change based on timing and complexity. She then gave me a cold stare and said (please imagine heavy up-talking here): "That's FINE. If you can't come up with any ACTUAL examples from your experience, you can use THEORY. That's ACCEPTABLE." Wow. Really? I just read a bunch of project management books and generated theory for 5 scenarios based on something other than my 20 years of experience? When I asked her questions about working at the company -- her responses were brief and did not answer my questions at all, such as "It's fine." I thought everyone there was great but the final interviewer seemed ill-prepared and also appeared to have already decided the outcome. Hiring manager asked me "how did it go" - and I said that I enjoyed meeting everyone, and that last interviewer was a tough interviewer. I didn't make any faces, elaborate or throw shade -- and his instant response was: "She used to be a kindergarten teacher - she talks to all of us that way [like we're children]." From what I understood from my questions to the last interviewer - she and I would not have been working closely, so I remain mystified as to why she was part of the panel.