I’ve never heard noone ever talking a thing about such structure of the mind, so this could be a cracked argument. But it’s pretty clear to me this is something real, as it’s what allows the fusion of things and the making of exquisite meanings.
Mindwalking is also something that can only be explained through this theory. Regurgitation too is an experience that begins in the second wall and I manage to bring it to the main frame and explore its potential. Also, sometimes the realization of the ongoing second wall of thoughts also seems to bring these derailed thoughts.
This perceivable stream of involuntary thoughts can carry some resemblance to the unconscious mind (as regurgitating feels close to dreaming), it’s an important discovery to make. And however unfooled experts of the mind might be towards these introspective wonderings, they’re having undeniable results.