A courteous interviewer would say something like "well, thanks for speaking to us but that's all we have time for - any final words?" Not just stand up all abruptly and be like "well... thanks, bye." You can see on Duncan's face that he wasn't expecting it.
Duncan also said on his twitter that he asked the man if he'd upset him, and the interviewer just gave "a bit of a rant and left"
https://twitter.com/Mucrush/status/742382916509028353