At first I was thinking -- What?! Take Karl back to camp and question the heck out of him!! Then I thought, aha, maybe Sawyer is going to follow Karl back to the Others town... Of course they could have questioned him and followed him back to his yard... But I guess Sawyer just doesn't want no more trouble with the Others, maybe getting caged, beat and almost executed made him a little nervous It is just the writers keeping us from getting answers.