I replicated the relevant part of the design. I put the same 4l axle into the same sort of Technic slot, it's specifically designed to be flush with those, so t

I replicated the relevant part of the design. I put the same 4l axle into the same sort of Technic slot, it's specifically designed to be flush with those, so there's no easy way to pop it out other than to push it out from the other side. I then used the "bush" piece to hold onto the axle from the other side, so you have to pull it out of that piece to get the axle out. It's not the exact same piece that's holding onto the 4l axle in the article, but from experience they've got about the same hold on the axle, so the difference won't matter. Yes it's annoying. I'm just pointing out that it's far short of the "can't be taken apart" claim in the article. I'd be willing to bet that it can be taken apart conventionally. You can probably push the orange piece a bit from the other side. Of course it will run right into the frame on the other side, but even Lego doesn't make components with micrometer precision, there's usually a bit of give in the plastic. If you can get some play in it of even a half a millimeter it'll be sufficient to do this with a toothpick instead of a sewing needle.