I don't think that "wall" is a literal boundary, so much so as a layer of actual space, since in that same sequence she throws it through multiple layers of space. Also, I don't think that space is literally the inside of Exostrider (as in, literally inside the suit) it's something more like the space Rover was in when they entered 3.0) in short, Exostrider acts as an entrance to the space rather than the space literally being inside the suit itself if that makes sense. Since obviously, the suit is not large enough for that. And if that's all that was required, the portal would be kinda useless. Ig we can wait for more story tho