The fact that she helped Clarie get away makes me think she is either scared of these people or feels like they are not the "good guys" they say they are. She may want to run away but, to where? Do we believe she knows about her mother being out there. If she went to the Losties camp she could get killed.
As for Carl I'm not sure. It feels like they have bonded. Maybe she's in love with him.
