No, actually, I'm pretty sure it's the world that's being lost. Should she be the subject, do you think she's missing the world? As in missing out? I guess it could be, but that's not how it came across to me.
I think what motivates her to get out is to go to a better place. Unless she's out for revenge against a corrupted world, helping the spirit more than herself.
In this case, English conveys the intended meaning and maybe the Spanish version could use a little fix. "Perdiendo" where? In what?
E.g., "le muestra [] un mundo exterior que se está perdiendo [en valores, corrupción, avaricia]", "un mundo decadente".
For the other meaning, "le muestra (todo) [el] mundo exterior que se está perdiendo".
I don't mean to be dense (sorry if I come off that way), I just enjoy analyzing meanings. Since we both seem to know Spanish and understood it differently, I think we can agree that it isn't entirely clear.