That does sound terrifying. I know what you mean when you say how clear it was. Auditory hallucinations, including voices, are the norm for me during stim psychosis but the voices were always in a different room - all except once. I was 16 and had just joined this site a few days before as I was on a minor speed binge and wanted people to talk to. It was only the 3rd day and I was reading a rather scary trip report on erowid. Then it was as if there was someone right behind me and they whispered right in my ear, ''he's reading it now''.
It scared the complete shite out of me and I bolted up the stairs to my parents bedroom and woke them up. When they asked me what was wrong, I realised how crazy it seemed and I just said, ''nothing''. I don't think I've ever felt terror like that, no matter how brief it was.
The speed was really crap but I had been bombing it rather than snorting it. I think the fact that I was abusing solvents at points of the binge might have had something to do with it. Some of my most insane, vivid, delusional experiences occurred when I used to abuse solvents. It's the only thing that's ever made me attack a mate, but I thought I was in hell and wasn't going to take shit from one of many faceless mannequins that were giving me the finger 8)