Can you ever end an interview early if you realize you're not qualified?

I realized a few questions in that I wasn't interested in the role as what I had hoped was a small part of it was actually the main focus and not a topic I'm strong in or want to pursue. Is it better to continue to let them ask you technical questions that you keep responding "I don't know" to and struggle through and answer what you can or just politely bow out somehow? I had the thought at least 3 times to just leave as it was a panel interview with them just staring me down and giving me absolutely nothing while asking me about manufacturing processes of various objects and diagrams in front of me.

Is it more rude to waste an hour or more of their time or to end it early on if you're sure you don't want to work for the company ever?

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