To be perfectly honest, I hadn't considered the fact that Tochi running around the ship would leave the Big Chair empty (or I had the days confused, at least). My fault for just jumping back into story telling as opposed to looking at the schedule and determining where he should be, I suppose.
That said, I also figure that, since the ship is basically just sitting there, there may not be anyone sitting in the chair in a literal sense. The Captain is in his Ready Room, Zai is running around the ship in pursuit of solutions and such... I presume that the next (most senior) officer would have been left with oversight... Or, as efficient as he is, Ferrero may have come on shift early and took the CONN.