It is said she deliberately did that to do him a favor. She had owed him a few favors before and he used them to coerce her into helping him a lot in future. This is hinted in the coming scenes.
WuJinYan & WangXingYue is a great pair. Watching The Double, I kept waiting for scenes where the two of them came together. Their unspoken attraction for each other is explosive ❤❤❤