I don't think i've ever slept walk, but I had something similar once...
When I was around 7/8, I was having this INSANELY realistic nightmare that my whole room was shimmering like it was underwater, and when I tried to wake myself up, suddenly I found everything covered in snakes. So I got up, started jumping on furniture/desks/chairs in order not to touch the snakes, and jumped through the door way. The wierd part of this is that I didn't really wake up from it, it sorta ended with me running through the hallway into my parents room. Maybe I was sleepwalking and dreaming and remembering it at the same time, or maybe I was hallucinating... either way... creepy...