Hey, instead of opening your eyes, why not try holding your noise and seeing if you can still breathe, like in Hargart's technique? Maybe by keeping your eyes closed, you won't completely wake up..?

I've experienced something similar to you, but it was during the WBTB method.. I kept seeing images in my room and hearing a LOUD noise, like my house was breaking! It really freaked me out, so I decided to sleep normally that night.