With what she's seen already, I dunno if Xia's willing to take that risk.  The dryads are risky up-close, she's seen that much just from that little exhalation.<br/><br/>Edit:  And she doesn't like the idea of letting them<em>steal</em>an adventurer.  As far as she's concerned, they've forcibly transformed her and that, combined with the ambush, is enough reason to attack first.