There are stairs further aft, but they aren't public. At least I don't think they are. I've only seen them opened during the lifeboat muster. I've you're in one of the deck 7 aft cabins, your muster station is in Animator's Palate. They open the stairways for the drill. This is how I usually get back to my room after the drill, as the main aft stairs and elevator are crowded.
But as mmouse said, during "normal business hours," I think you have to take the aft stairs (near the elevators) to deck 7 and then walk back. It's not too far.