Who? Luffy will not be there, thats Obvious, or else luffy and shanks win.
The crew of BB will take care of Ben and everyone else.
here is the thing mate you are creating a scenario in which Shanks will die ... for no good reason
Oda RARELY KILLS and ONLY kills for big reasons
Roger had to die so we can have a story
Ace had to die cause he had a better claim to the throne
Whitebeard had to die cause Teach should've replaced him
you want to kill Shanks in a made up scenario? consider something called "story arc"
dying cause Luffy will get mad is not story arc
Luffy already have more than enough reason to fight Teach
he BARELY had any personal reason to fight Kaido