Perhaps the whole deal with the pit of death in the throne room is that it's unfinished, and oce it's finished construction, the Emporer will have a Bond villain style trapdoor over the pits, which he activates from his chair to drop unruly underlings (and his guards sometimes if he's bored) to "witness the power of of the fully armed and operational battlestation", for roughly 1/10th of a second before they get vaporized.
On a completely unrelated note, I always wanted my own version of the Emporer's chair as a kid, I thought it was the coolest chair ever. Still think it's pretty nifty looking.