This isn't possible because we know that Jinbei had a clear view of the fight
before Zoro even heard Sanji speak
He literally says "
I see him"
And we see him react to the attack right after
So he very clearly saw what happened/the damage that was dealt and decided to assist him afterwards
Jinbe wouldn't attack for him no reason
If Lucci was clearly defeated and looked like he'd no longer be a threat then Jinbe would have no reason to hit him
In Jinbe's case he can remove the threat in 1 of 3 ways
Knock him out, kill him (never gonna happen, this is One Piece), launch him far away (stupidest option but no surprise that this is what he chose)
Why would he have a better grasp on the situation than Jinbe? It's not like either of them can see HP
Plus it's not like Zoro is totally against other people finishing his opponents