> When I got my Vive and was playing around in The Lab, and one of the experiences puts you on the side of a mountain, I stepped off a cliff edge and I could feel my heart rate increase slightly as my brain was expecting me to fall to my death. The immersion is real.

Not disputing anything you're saying but I actually have this same experience playing games where you can fall and the player accelerates (particularly if the camera is first person or right behind the player). Just looking at the screen when I jump off a cliff in something like WoW makes my stomach feel like 20lbs of iron while I'm falling. I've kinda learned to enjoy it at this point.