I don't intend to implement this in my approach, however... two main reasons.
First... I consider this to be a dramatic "safety issue." The only reason I can envision for wanting a person inside the lift shaft (other than poor scriptwriting) is for extraordinary maintenance (when the tube would be shut down... and most likely in zero-G as well) or if a car was permanently lodged in place by a mechanical failure of some sort (and even then, this wouldn't be the first choice, since the majority of the time you could get access through an existing door panel or through a bulkhead).
Second... we've seen ladderways in the ship, and even know where they are (at least in the "central corridors"), on-screen.
The biggest problem with doing this sort of design is determining the line of separation between "earthbound engineering" and more application-specific engineering. I'm afraid that this idea, to my eyes, falls into that category... carrying too much from earthbound "elevator shaft" design into a dramatically different application.
I like most of what Shane has done, but I don't consider his work to be authoritative (then again, he probably won't consider mine that way either, and since it's all fictional that's perfectly fine!
Can you give me a reason I haven't thought of for having the tubes (which are currently close-fitting to the exterior of the car) enclosed in a volume which incorporates a trio of ladderways?
At MOST, I can envision some handholds in the smooth metal tubing along one edge... not easy to climb, but serviceable in an emergency. But I'm having a hard time imagining a time that you'd really need to use those...