The mind works with benchmarks on a constant basis. Everything is a comparison - to your prior experiences, other people's experiences, your identity, etc etc etc

Introducing a new benchmark creates a new perspective to measure old perspectives against. In essence, de-sycing your perceptions of self, reality, etc until the new and old normalize out.

(You see this with psychedelics a lot which is why it can be such a valuable therapy for depression and PTSD)

It is no wonder that being put in a giant space bullet, shot into the darkness of space, with the light of your world reflected back at you like the ultimate out of body experience leads to an "observer" sensation.