Even in the manga we never see Sanji knock out PO. You want me to show that he's fine but you can't even show me that he's knocked out. Sanji attacked him and then he left. He didn't need to beat him to survive. Yes, I do agree that PO failed his mission since he was there to kill Sanji.
Why would he need to bring page one back yet when there's nothing that happened in the manga for him to return. We haven't even seen the other flying sixes, not counting Drake. Are you saying that there presence is also are needed?
So let me get this correct if I step in the ring with Mike Tyson in his prime and he knocked me out then I tied with Mike Tyson.
Killer was there to kill Otoko and anyone that interfered. Not only did he fail his mission but Zoro knocked him out. Zoro was standing over his unconscious body prepared to fight the fox.