Didn't danzo get killed on the bridge and respawn on top of a stone pillar. That's a significant distance. And if you refer to danzo's speed feat against sasuke while kidnapping karin, his shunshin speed is quite fast as well. At worst he can respawn pretty near Hiashi andthen shunshin to cross the remaining distance.Danzo's never shown to respawn beyond what, five-ten meters at most from his original position. I doubt he'd cross around and behind Hiashi with it, suddenly. Don't even think that it'd make a large difference, though. The Air Palm is a quick jutsu, he can hit Baku almost instantly once he appears or the suction starts.
Is this manga intel? If so Hiashi definitely isnt using air palm the instant its suction begins. It took Sasuke a little time while he turtled in Susanoo before he came up with the strategy of using fire style. I doubt Hiashi can perform air palm while hurtling through te air towards Baku. Or he uses rotation, which means he cant sinultaneously use air palm.