My guess:
Luffy's group and Kid's group will meet up next chapter at the 3rd floor entrance. They are literally running into each other.
Both groups will encounter Black Maria.
-Killer will stay behind to fight Black Maria on 3rd floor (
997)
-Jinbei will stay to fight Jack on 4th floor (
998)
-Sanji will stay to fight King on 5th floor (
999)
-Luffy and Kid are the only ones to reach the roof and face Kaido and Big Mom (
1000)
Black Maria does have swords to deal with Killer: