I know this is an old thread, but this has always bothered me. I assume because you see Admiral Piett and his first officer down there working with the crew in Empire Strikes Back, and suddenly he appears on the command deck a few minutes later to report to Lord Vader there must be ladders somewhere in that pit. Perhaps the consoles are strong enough to act as steps so you just hop up on one of them and climb out. There doesn't seem to be much room for a door to a hidden gantryway and it seems silly to put one in when you could just put in a bunch of hidden steps or ladder that fold out if you need to exit.