Not sure how it is now, but in investment banking interviews, interviewers definitely used to be rude or obnoxious sometimes. To an extent, this was a deliberate move to test a candidate's reaction. If the pressure rises when the market goes south on the trading floor or when preparing an important presentation for a merger, temper might rise as well, and there is little time for niceties. Dealing with it reasonably graciously is an important qualification for working in that kind of environment.
Now, I'm not advocating being an asshole. But when working with top people in high pressure environments it certainly helps if you can deal with assholes. It is a bit reminiscent of Postel's law: Be strict in what you send, but tolerant in what you accept.
In this case, it could be that there was some other important meeting the person had to attend, and didn't want to interrupt the interview process with an explanation or goodbye.
If you conclude that this is not the environment you want to work in, fair enough, and concluding the interview politely at that point would certainly have been an option - it seems that the organisation and you were not a good fit anyway.
Now, I'm not advocating being an asshole. But when working with top people in high pressure environments it certainly helps if you can deal with assholes. It is a bit reminiscent of Postel's law: Be strict in what you send, but tolerant in what you accept.
In this case, it could be that there was some other important meeting the person had to attend, and didn't want to interrupt the interview process with an explanation or goodbye.
If you conclude that this is not the environment you want to work in, fair enough, and concluding the interview politely at that point would certainly have been an option - it seems that the organisation and you were not a good fit anyway.