And a get outta jail free card is going to be the letter of engagement that the client gives you.
免责卡就是客户给你的委托书。
英语百科
Engagement letter
This article uses the word engagement in a legal sense.
An engagement letter defines the legal relationship (or engagement) between a professional firm (e.g., law, investment banking, consulting, advisory or accountancy firm) and its client(s). This letter states the terms and conditions of the engagement, principally addressing the scope of the engagement and the terms of compensation for the firm.