We don't inherently get trapped in a "shell" by autism, we just learn to code-switch and act more neurotypical, with varying degrees of skill, when it serves the situation. We aren't "trapped in our own world", we are so connected to the world, and experience it so intensely that we have to cope in a way that looks "antisocial" to the uninformed. That's just how it looks to the outside. If anything, masking by performing actions like forced eye contact are what creates a shell, because it means we aren't being our true selves, acting out the moments where we mask as if we are reading lines from a script, and possibly dissociating in the process.