Hi, Zesty, yes, you have to go 'through a wall' a ghost wall as it is called by the hint outside (that structure, where you had to go up those stairs for this clue), but there's no button, stairs are behind that wall, which lead into the warehouse ...
When I managed to reach it I've taken two pictures which I will post here, so that you or anyone else may at least see what you are looking for lol ... this kind of 'passage' looks similar to all the other half-round staircases one might say, but they're not as much so, but just have a look ... Those pictures just show you how the passage looks, it actually doesn't spoil anything else, means how to get there lol, so please enjoy nevertheless ...
- Show Spoiler
I was coming from this side, I had to turn to the right to have this view ... The second picture is taken from the other side with the view onto the corner of the first picture, maybe that helps ...