> My brain feels like it's been relieved of the task of managing the moment-to-moment decision. Instead I start noticing moves 3, 4 steps ahead as time slows to a crawl around me.

I think this is a common sensation to many who have trained playing an instrument enough. I get into that state every now and then when playing something on my guitar, it's like I can curiously observe my fingers pick out the melody I want to play, without thinking about or taking much conscious action in it.