Marco specifically said he was holding off 2 guys with above 1 billion bounty in chapter 1006, he obviously didn't mean its only for a second its since chapter 1000 where King and Queen failed to stop Marco from sending Zoro to the rooftop. Which is why King saying he is busy enough to not even go to finish 9 scabbards is important in Ch.1004 then we see Marco vs King and some flying gifter in Ch. 1005 then in Ch.1006 before Queen could attack Hyogoro Marco stops Queen then King tries to cheap shot Marco while Queen was also attacking Marco with a laser but King ends up on his butt with a bluebird attack then a flying knee makes King bleed from his mouth, before Queen can cheap-shot Marco in return Marco sends Queen flying too. In chapter 1007 Marco holds Queen's neck and lets Chopper slap him.
It wouldn't make sense for King to fooling around and take damages from Marco when he needed to go and finish 9 scabbards, he was focusing on Marco, so your ''what we see counts'' only logic doesn't work due to Marco's statement on holding off both Queen and King in chapter 1006 and King saying he is busy in chapter 1004. The only reason King couldn't go anywhere else was Marco.
Marco's dialogue says nothing about how long the fight lasted. Holding off two commanders can be pretty tough even if it's only for a few seconds. Even Sanji lost so easily as a matter of fact. The panel in which King says he's busy doesn't imply in any shape or form that Queen is involved in the fight. I don't even get how and why King saying "I am occupied with Marco" = I am fighting Marco along with Queen. Once again, we clearly saw King attacking Marco with no sign of Queen or his attacks near them.
Queen is chilling around watching Hyogoro decimate the live floor. He's been out of the fight for so long that he forgot about Marco, and he had to remind Queen that he is his opponent with a bitch slap.
Marco right here^ looks far more bruised than he was in chapter 1005 proving King is the one who damaged He damaged him even before he resorted to using a cheap shot. King made it pretty clear that he can't go after the Scabbards and BM as well as Jack offered to go after them. So I am not sure why he'd be so worried about them. Also, If King really wanted to go after the scabbards so badly; then it actually makes no sense for the two calamities to fight Marco when King can do it by himself. King fought Marco when Queen is fighting Chopper, and he continued to fight even when Sanji entered the stage. So he can simply offer to hold off Marco and send Queen after the Scabbards if he wanted to.
Exactly, The only reason why King can't go anywhere is that he had his hands full fighting Marco in a one-on-one.