Maybe it's just the way Yukari talks but I don't quite get what she's trying to say?
By winning does Ran lose her right to give Chen orders or the choice to do so?
And if she loses is that all null and void?
"Right now, could you give her any order she will be able to accept while hurt?" "You realize it's all over if you choose your words poorly?"
If Ran cannot give an order than Chen would be willing and able to obey, and follow-through as a proper Master, it likely has consequences comparable, or perhaps worse, than simply losing to her. Ran does all the work herself, but Chen *wants* to work/receive orders. The lack of work/orders has her fighting against Ran. If Ran doesn't consistently give some after winning, it'll just make things worse.
If Ran loses, Chen is no longer her Shikigami/Ran cannot give her orders, and Chen will likely go off on her own, and do her own thing. If Ran wins, she has to start treating Chen like a Shiki, which means giving her orders. This is very much a "Heads I Win, Tails You Lose" in favor of Chen, if Ran is the sort to handle everything herself like Chen stated.
