The unified mind/body doesn't require conscious thought to operate. They aren't standing side by side with the mind leading the body in any conscious way. Mind/body is an integrated, single thing. And while the word "ki" is a label it's also the thing itself. We all have minds, we all have bodies. But without having mind and body coordinated ki is not manifest.
I think ki is the thing that binds mind and body and is present at all times to various degrees of intensity or awareness - what really gets the mind/body connection clicking along well is the level of ki cultivation development within the body - at first, most need to make this a conscious effort and eventually it gets conditioned to be unconscious and more natural in all your activities. - just my opinion based on my ki/qi model.