Hi Dev, and welcome.
Having been down the accident route several times and had multiple surgeries too this is a question I've pondered as well. To the point of trying to hold on to consciousness as an anaesthetic was given to me before surgery (the initial injecton) - although with no luck, I just blacked out. (probably just as well
)
My best guess is that what we perceive as self consciousness is just a dream run by the much larger, more collective and higher aspect of mind (still a part of ego) we don't normally have conscious access to unless we're a very accomplished spiritual practitioner.
That dream it's taught is designed to keep us bound to this reality - to have us believe that this world/universe is the only reality, leading to beliefs and attachment which further reinforce this. The thinking intellect, brain and body are a part of the reality too.
My best guess is that we black out in incidents like you describe because whatever happens shuts down the thinking intellect - which is all we're truly aware of in this dream.
That doesn't mean we don't have all sorts of existence at higher levels we're aware of too (but in some other state), but the analogy I've heard is that it's like waking up from a dream - we snap (or as you say 'click') from one reality to the next and in the normal state don't necessarily retain any memory of the last.
This is possibly similar to snapping from an OOB state back to normal awareness - the skill we're trying to learn to go OOB is surely not how actually to do it (we seem to do it all the time), but rather to retain awareness is our normal state of consciousness while we are doing it.
That's just one view, be interested to hear what others have to say. That Chinese gentleman sounds interesting, especially if he has a real understanding of what he's doing...