The chief officers - the generals - were assembled together in Jehu’s quarters, perhaps holding a council of war. The place of assembly seems to have been the great court. Hence, Jehu “went into the house” 2 Kings 9:6 entered, that is, one of the rooms opening into the court.
Related Commentaries of 2 Kings 9:5
2 Kings 9:5
5 And when he came, behold, the captains of the host were sitting; and he said, I have an errand to thee, O captain. And Jehu said, Unto which of all us? And he said, To thee, O captain.