"The instruments that almost killed that dude were the ones the nurses left in, OK?" Ken quipped back ... adding: "The ones that saved his life are the ones I left in. And besides, I only had the gig for 10 days at that point."
Ken and Joel's joke stirred up plenty of laughs from the A-list crowd ... and comes hot on the heels of Jo explaining he didn't have enough time to prepare for the GGs ... and also blasting the audience as "marshmallows" who couldn't laugh at themselves.
You'll recall ... the comedian clearly didn't get the response he was looking for when his cracks on Taylor Swift and the film "Barbie" fell flat.