“Everyone has a plan until they get punched in the mouth.”
I think the cold legitimately threw him off. Not that he was feeble from the cold. Just that it made him more easily flustered and he snowballed.
I’ve also had interviews that I was “prepared for.” But trying to remember all the information at the moment was difficult. Hell, I was told one of my interviews was the best they had ever seen, and the last question had me flustered until I finally came up with my talking points after a minute.
That’s what it felt like to me, a flustered man in a bad interview that snowballed.