Yeah, I can very much sympathize with your friend. One thing I've learned is that setting an intention is important, and not being reckless with it is important too. There have been a few time where I've come back home after a night out and dove right in with half drunken bravery, and yes infinite thought loops are a thing! There was one time where I quite literally thought I had died and landed in hell and in that moment of time an indescribable suffering was transmitted through my being via some kind of demon which left me in tears for about a half of an hour afterwards. But lest I drive the curious away, whenever I have gone into it with respect I've had experiences that were deeply enlightening and, while always weird, seemingly benign.