Okay, dude, seriously. You need to relax. Caaaaalm down. You aren't interviewing for Top Secret security clearance or something, this isn't a life-or-death situation. You really need to stop looking at the small details. Don't focus so hard on the trees that you can't see the forest.
On this question: If they don't ask you probing questions, THEY have failed the interview. No initial answer should ever be enough. Even if they get as much as they wanted to from the question, they need to ask you more and find out how you respond to followups, whether or not you can think on your feet, etc. An interviewee who has the greatest answers in the world prepared, but can't elaborate or tell the interviewer about the situation from a different angle, is an interviewee who shouldn't be hired. And an interviewer who doesn't try to find out if that's the kind of an interviewee he's dealing with has no place being an interviwer.