At the suspect's house, Maggie says "What's up?" and one of the S.W.A.T. team replies "Behind the bookcase." There was a door behind it, but it wasn't visible until they moved it. There is no way that the S.W.A.T. officer could have known that it was there unless he moved the 'bookcase' and then (improbably) moved it back. Moreover, it was a Welsh dresser (china hutch), not a bookcase.
After looking at the fully clothed, dead body in the street, Scola announces that he had been shot by a 9 mm weapon. There is no way that he could have known that.
When the agent move to enter the suspect's cellar, OA says "Cover me." However, his large frame blocked the doorway and there is a narrow staircase down, beyond the door. There is no way that the others could have covered him.
Jubal only leaves the JOC when it is absolutely necessary. However, he arrives at the crime scene for no other reason than the dramatic effect of him being perturbed at possibly recognising the victim.