There are also queries like "Who won the battle of Waterloo?" which are going to lead to a lot of 2 second visits whether visitors like what they find or not. It only takes a second to get the answer and then leave happy.
I'm thinking Panda must work differently for different types of queries. If a query like the above can be answered in just a few seconds, then bounce rate is useless for determining how well the site addressed it. In fact, it could even be misleading. A site that doesn't answer the question well, but keeps a user thinking it might, could retain a user for a while before they realize they're wasting their time. Hmm, that might explain why Yahoo Answers (from an army of uninformed dolts typing whatever comes into their heads) ranks well - because no one can find a decent answer there!