"if the woman disagreed with the policy she should have resigned"

That's a fundamental misunderstanding of the situation and the issues it raise. Sally Yates is responsible for ensuring adherence to the law and the constitution; it's her job to tell the incumbent President whether what they are doing follows the letter of the law. In this case, she did the only thing she could. She swears an oath to the constitution, not the president.

Nice to see you're supporting the breakdown of law and order.