Salt is practically mute all the time, so we can not really empathize with what she goes through (although arguably Jolie is at her best here), or what motives there are, if any, because to empathize one has to speak. And when Salt speaks, it is mostly to herself, via flash-backs, that have no actual relief, in the double sense of the word, if one has to talk about double things, since double things, well, semi-happen on screen...