Until I experienced, I did know that such a thing existed. After the panic attack I searched about and found an entire Wikipedia article describing it.
To your question, I think third person view is like an intellectual activity that one undertake voluntarily. However what I experienced was very real feelings of separation and not an intellectual role play.
I think we all dissociate, like it's a spectrum; the weakest most minute manifestation is when we just 'take a step outside of our current state' you know, when you stretch just a bit to be/think/do slightly different. Experiment. Mimicry. We temporarily sever/disable a few 'links' inside and let new connections form, just to see.
It's also how I picture resisting empathy, all these times when we shut down feelings almost automatically — some of it is mundane 'keep a straight face', some of it is deeply atrocious like awful news or misery right in front of you. We have these "mirror neurons" that automatically replicate emotions of those we see¹; and unless we shut it down or temper it, we are bound to feel that very thing too. I think we kinda "dissociate" mildly from these mirrored feelings whenever we must, it's automatic by now (social species must do that to evolve beyond primal emotions it would seem).
But sometimes dissociation gets out of hand, cranked up to 11, and it operates versus parts of your own self, it shuts down entire regions of our inner world, and what's left to see is a weird, paradoxical state, that which psychology and the DSM see and would rightfully call pathological etc.
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[1]: That got me thinking, maybe it's one thing people born blind can't do: "see" the emotions of others and trigger mirror neurons in that way. Maybe there's something in this, in the unsufferable realization that you may see but never really know what's inside others, that drives schizophrenic people so obsessed whereas blind people, obviously, can never experience such a feeling. It certainly converts to other senses (voice conveys so much emotion for instance), but hypothetically very differently. I don't know. Thinking out loud here.
> I also experienced myself and my thinking self as two different entities and it as if I could watch myself as another person.
Can you expand on this? How was it different from the "third-person" kinda view that we do casually?