I'm not sure I've got a proper answer from T about this.

But I have a thought. Eg, I'm being followed.
Then my body reacts as if it is happening and I then full on believe and act in accordance to that.

Or

I can read someone else's terrifying experience as it's happening to them now and I immediately become that person and my body reaches accordingly again.

Does this make any sense?

I do have complex ptsd. So maybe because of the many traumas I've been through this is just a natural thing considering.