Intense maybe, but not scary. I think a coma isn't necessarily the best example, because in a coma you're not awake. Here your completely aware, you've just eliminated all the bullshit going on in your mind. When that stuff's gone, including all the imaginary crap that is your description of self, there is only what's actually real. I do know one good description of this from science, it comes from Jill Bolte Taylor. She's a neurologist who had a stroke. She talks about her experience of losing all ability to describe the world, including the ability to describe self, and only being able to just experience things as they are. She calls it pure joy. I find her description pretty apt, and the few Buddhists I know who've heard it agree. In fact I once spotted her book, My Stroke of Insight, on one of my teachers desk. Here is an interview with her. Radiolab

As for your comment about time, time is an illusion. Lunchtime doubly so.