I have a much different take on immersive writing which is much easier for a writer to implement.

If you notice, in the Fear and Loathing example, the action starts right away. There's a drive underway, drugs are being had, we are in California. What next?

As readers, we simply have to trust that all will be clear in due course.

Saving Private Ryan and the first Daniel Craig Bond movie, Casino Royale, with the parkour scene start the same way. The viewer is simply thrown into the cauldron.

If you can keep the action coming, the reader will tag along.