Is it possible she was pretending in Season 3? Through the flashbacks, it's been revealed that her character wasn't who she said she was (rather, she was an experienced operative employed by Widmore). And her last act was to make Kate think she was on her side only to secretly betray all of the Losties. Anyway, I thought it was a really solid episode. Certainly lighter, but I felt it was more in the style of classic Lost. The season's been moving so fast that it's hard to really care for these characters - the very element that made the show great to begin with. This episode also contained one of the more emotional moments of the season while also setting up the story for the next few episodes in the season.