[Terr_]

I think there will be a lot of difficulty with wording and meaning here, because we don't have a consistent terminology for the different kinds and levels of immersion or focus.

For example, the distinction between being deeply involved and distracted in a game (which does not require special tools) versus the extent to which the game will trigger automatic bodily reactions.

In other words, someone deeply "immersed" in a chess-match isn't quite the same as someone "immersed" in a VRv game so that they fall over at a jump-scare.