Answer:
It is difficult to get a cult member out because it can get dangerous for everyone involved, including the member. Cults are extremely strict in most, if not all cases. If a member joins then tries to leave, other 'loyal' cult members and leaders would fear that if they let him/her go then their secrets will be known. They might not even let the member leave in one piece or leave at all, depending on the situation.
hope this helps :)