Hmmmm... Iliette backsory wise is really just a pugilist/lancer mix that travels all over Eorzea to get stronger for her own means, while she is friendly and cocky most of the time, she does keep people at a distance.
She may have found a piece of crystal and like any good adventurer tried to flog it for the highest price, but nobody knowing it's worth except the garleans (and by no means will she sell out her own country for them) she hid it at a safe place.
Or you know, you guys are next on the execution list (because you guys didn't comply or outlived your usefulness) and got thrown into the same cell as her, while she is waiting for her own...
She may have found a piece of crystal and like any good adventurer tried to flog it for the highest price, but nobody knowing it's worth except the garleans (and by no means will she sell out her own country for them) she hid it at a safe place.
Or you know, you guys are next on the execution list (because you guys didn't comply or outlived your usefulness) and got thrown into the same cell as her, while she is waiting for her own...