If you can't pull it off when the time comes, it may be easier for you to sing the line, a slight blues inflection adding to the emotional impact. Either way, you'll need to follow it up with a long medley to be sure there are no gaps in your playing; no threat of further conversation. I'd suggest playing a little Sun Ra, some atonal free improv, and a few particularly inaccessible originals of your own. Your antagonist should lose any interest in hanging around, and you'll once again be safe from direct human interaction.
I'm curious: If annoying people like him were to stop asking you such ignorant questions, do you think you might feel like playing an extra hour or two just for fun?
Have a question for Mr. P.C.? Ask him.