FasterN8
Interestingly, previous editions had a "RAS override" that let you still control your meatspace body while in VR, albeit with a hefty penalty. It meant you didn't go full ragdoll in VR, though, and the penalty was mostly to actions not movement.
Interestingly, I don't think the writers knew what a reticular activation system really is, but they went with it anyway. Still, I'd easily houserule that back into SR5 at my table, and I wish they'd bring it back so it was missions legal too.
In theory, it already exists because any time you slot a simsense chip and retain control of your body, such as with a Personafix chip, you're technically using the same RAS override from previous editions.
But to be fair, deckers going ragdoll is the Matrix equivalent of the magician astrally projecting.