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.
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. His "future self" warns him of a flying chair headed in his direction, saying "Watch out". Also the position of the "future" O'Brien has him lying underneath the bar counter at the time.
Fast forward to the scene (17.10) where the actual bar brawl is taking place. The "present" O'Brien remains standing during the whole fight scene. Also the "present" O'Brien warns the "past" O'Brien to "Watch the Romulan," which is completely different to what he had said in the previous fight scene.
The two scenes are inconsistent, but this is not a goof. Because O'Brien now has foreknowledge of the events that will happen, he is able to make adjustments as the events unfold. For example, he is now able to dodge the blow from the Klingon that knocked him onto the floor the first time around. That is why he remains standing.
Miles O'Brien is shown wearing 1 dark pip on his collar, pips are for commission officers and he's a senior enlisted member.