deadsea - 6:10 pm on Oct 9, 2012 (gmt 0)
I'm pretty sure they use click through rate and bounce back rate on a per-term basis. Unhappy users for one term shouldn't hurt the page's ranking for other terms.
Although Panda appears to me to have site level user satisfaction metrics weighted heavily into it. Google seems to be saying "Users don't appear to be satisfied on this site no matter what terms we rank them for, let's flush this site down the toilet."