Emergent property through evolutionary selection, do you not believe in evolution?
If the brain is just processing things in complete chaos an animal would be completely useless, but with a part/thread dedicated to processing inputs and checking memory I think it is very obvious this function of consciousness would emerge through natural evolution.
Yes, to me they sound like similar questions as can a human-level AGI robot experience consciousness like we do, or is consciousness a purely physical thing. My opinion is yes to both but I guess i'm a physicalist/materialist.
Actually another comment points out something interesting, when we get black-out drunk we are basically in this zombie-state. We can talk and hit our head and physically our brain still reacts, but it was like we aren't actually there and our body is just on autopilot mode.