I can only imagine that you are talking about the stairs that are at the VERY back of the boat. Their is a small side halway with steps that goes from TopSiders to Deck 8 cabins. If you head to the back of the ship from there, there is a set of stairs that connects from Deck 8 to 7 to 6 to 5. There stairs are open to the public (and are located in the area of the "secret" Deck 7 aft deck). From there, the stairs split to the sides and lead to the back doors of Animators Palet. However, this is NOT a "secret" back entrance to Animators as those doors are only used in emergancies.
Basically, the whole purpose of these stairs is to really be the emergency exit for Aft cabins that with assymbly stations inside Animators. But for the stairs from Deck 5 to 8, they are a nice "short-cut" to Topsiders if your cabin is in the Aft section of the ship. If you are forward of or near the Aft elevators/stair case, then it's easier to get to Topsiders via the "normal" stair cases.