The entire interview went by and no one realized anything was wrong.
I’m not sure how a disruption of a live interview would be any better, especially given that he only realized something had gone wrong when the presenter was introducing him on live TV.
The live interview was already disrupted when they started interviewing a random person as an expert. Everyone watching being misled, to me, is a bigger disruption to the interview than admitting something is wrong.
IMO the best thing to say is something along the lines of "I think there's been a bit of a mix-up, I'm not the person you think I am, but if you want my two cents anyway ... ".
Obviously in reality I would've fumbled worse than this guy did, its easy to think things through with the benefit of not having the pressure of being put on the spot on live TV.
I’m not sure how a disruption of a live interview would be any better, especially given that he only realized something had gone wrong when the presenter was introducing him on live TV.