Even though it's fun seeing Luffy and Zoro bros cry you gotta chill out. How many times has Oda let superior oponnents fight weaker ones?
The Seraphim are supposed to show off.
Law and Kid both won't lose. They represent the new gen. They might lose the purpose of the battle which is the RP but they won't lose the fight.
Also, the Giants might intervene. They're surely grateful to Kid and they like Shanks.