She is handling this pretty well. Zari relaxes just a fraction. May as well give the harsh truth up front. "The catch is if I pull off saving you, I am one step closer to saving my brother." Laurel is a means to an end. "I might not pull it off." Also a problem. She thinks she caught every angle, but unfortunately she's been wrong before.

"The reason why it's you? Your sister saved me. I figure I owe her one." The fact she's on her team of losers has nothing to do with this. Or that she cares about Sara's happiness. Totally just paying her back.