I guess it would be okay in sleep mode. After all, we aren't in REM sleep for a while right? You should be carefull though.
I once fell asleep on the couch at my grandmas house. They started watching a movie After I went to sleep. I had a very Vivid Nightmare that a king cobra snake was crawling up my body slowly........! It was almost to my neck when my Grandma woke me up. She said I was gasping and sort of sqealling in my sleep. I wasn't lucid, thank god she woke me. I was freaking out!
Then when I told her what I was dreaming she said that they were watching a movie about that very kind of Snake. So the TV , radio must sneak in there into your subconcious somehow.
star****