When Chief O Brien is in Sisko's Office with Jadiza, he Time Shifts into the Future where he is In Quark's Bar and a Brawl is taking place and his "past self" warns him of a flying chair headed in his direction to "Watch Out" .
Also the position of the "Past" O Brien has him lying underneath the Bar Counter when he warns his Future self.
Fast Foward to the Scene (17.10) where the actual Bar Brawl is taking place has the "Present" O Brien remain standing during the whole fight scene.
Also the "Present" O Brien warns the "Future" O Brien to "Watch The Romulan" which is completely different to what he had said in the previous fight scene.
Sisko told O'Brien to maintain light duty and specifically told him he didn't want him crawling about any Jefferies tubes. The crew was on a Cardassian built space station though and wouldn't have any Jefferies tubes.
"Jefferies tube" is a Starfleet term for maintenance conduits that run throughout a starship, DS9 has plenty of maintenance conduits so technically the station does have Jefferies tubes.
Miles O'Brien is shown wearing 1 dark pip on his collar, pips are for commission officers and he's a senior enlisted member.