Good answer, but I'd also add that since Buffy is a Slayer, she is stronger and heals faster, which might have contributed to her surviving that.If I recall correctly, Buffy was shot on the upper chest, off to one side, left, I think. A bullet there would penetrate a lung, which is serious enough, but not instantly fatal. Apparently, Tara was shot either in the heart or so near to it that the trauma caused it to rupture, which would ne almost instantly fatal.