On the PS2, choose the map Tantive IV: Interior during the Clone Wars era, now go to the median room as you see in the map. Then jump twice and you can find yourself jumping through walls and ceilings, and if you do it through a ceiling you are walking on top of the ceiling. If you do a run speed boost and then jump you will go through the walls. If you do the same thing as a Clone Trooper then speed boost into the walls you will get stuck and you are visible to any droids, but you can't see anything.