>>If he said something closer to "Thank you all for your time. You're doing fascinating work but I don't think that this would be a good fit. I really enjoyed meeting you all and maybe I'll get a chance to work with some of you on a future project." and they decided that was burning a bridge then that is a bridge worth burning.
That is certainly not the impression I got from reading the OP :
"At one point when he was asked to move to another conference room he decided he had enough and said that he was done with the interview and wanted to leave."
"When he went to leave the lead jumped into the elevator with him and asked him why he didn't want to continue"
We're forced to interpret a 2nd hand retelling of the events, but everything points to this individual leaving relatively abruptly. Why else would someone feel the need to run after him into the elevator?
We have way too little to go on to actually decide which way the candidate went. We have one side of the story second-hand filtered via our own interpretations. Thing of it is, given just what we know I could spend ages listing out credible ways it could have gone given what we have.
Assume that the candidate did give something closer to my latter statement. Perhaps the lead wanted a better explanation of what made the fit so poor. Perhaps the lead actually could not comprehend anyone not wanting to work there. Perhaps the lead didn't believe the explanation given. Any of these could feasibly lead to the same account we're given, as could simply leaving abruptly or literally saying "fuck you, fuck this, fuck everything".
And my point is that there's nothing to indicate that this candidate was particularly undiplomatic so it's rather senseless to attack them for burning bridges. This is a situation where, given sensible people, bridges will only be burned with the particularly undiplomatic route.
That is certainly not the impression I got from reading the OP :
"At one point when he was asked to move to another conference room he decided he had enough and said that he was done with the interview and wanted to leave."
"When he went to leave the lead jumped into the elevator with him and asked him why he didn't want to continue"
We're forced to interpret a 2nd hand retelling of the events, but everything points to this individual leaving relatively abruptly. Why else would someone feel the need to run after him into the elevator?