It was 6-5 Red Sox, second and third, two out, Torii Hunter at the plate and Vlad Guerrero on deck. Terry Fancona's decision was to have Papelbon walk Hunter intentionally, load the bases and pitch to Vlad.
The IBB to load the bases is one of the most overused overmanaging tricks in baseball. It makes sense only when you desperately need the DP (not applicable with two outs) or occasionally when there is a very good hitter at the plate and a very bad one on deck. And here we're talking extremes, where for starters you should only consider the move if the current hitter's batting average exceeds the on deck hitter's on base percentage.
With two outs, it's basically never the right move to walk the bases loaded to pitch to Vlad. It wouldn't have been the right move to walk someone to pitch to Hunter. You don't ask your pitcher to load the bases so he can pitch to a good hitter. With the bases loaded, a walk is too damaging, as is a HBP -- plus the knowledge of this fact turns the pitcher into a poorer pitcher who no longer can so easily come inside, throw to the corners, or pitch from behind in the count.
Vlad singled home two runs to give the Angels the lead, and ultimately the win and the series. Sometimes it plays out as it should.