What experience do you have speaking with C-level clients?

Initial screening interview and phone interview with hiring manager focused on standard introductory questions about my background, how I learned about the position, how much I knew about the organization, why I was interested in the job, and what value I could add through my previous experience and skills. They gave a heads up that the in-person interviews would be mostly behavioral (e.g. tell us about a time you overcame a challenge) but one of the hiring managers switched things up with more rapid-fire hypothetical questions that both caught me off guard and seemed scattered, as the questions she posed were rather large and would require a bit of thinking and planning yet she did not allow much time for an answer before skipping to the next.