Kate was worried. Not because of anything that had to do with this island, they were stranded on and it's Others and other weird things. No, she was worried because of the other group that had joined them coming from the tail section of the plane. She had heard Jack say that Ana Lucia was a cop and if there was a person in the world Kate would not like, it would be a policeman. However, right now there was one around her, who could recognise her real identity. Kate's worst fear was, at the moment, focused on what would happen if the truth came out and Ana Lucia did know why she was a convict.
A shudder went through Kate if she thought about a possible reaction from Jack. Her fear even increased when she thought about Sawyer and his look on his face if he got to hear it. Then there still were the rest of the survivors, who probably wouldn't want her near them again. Kate would be all alone out here, with no one to care about her or worry whether she was fine. Jack might never look her again in the eye.
Luckily, it wasn't that far yet. Until now, everything was fine and she and Ana Lucia hadn't spoken a single word to each other. Maybe, Ana Lucia hadn't noticed anything at all. If she did, Kate would explain everything to Jack from her point of view with which she might save herself a little gratitude. Still nothing had happened and it probably would stay that way, but worries remained with Kate, because Ana was eyeing Kate sometimes with a little too much interest. Kate knew deep inside she had already been recognised, but wasn't going to admit it to herself.