I actually got locked in my dream whilst fully awake a couple of months ago...
Was working away in Scotland, was in the hotel room with my buddy who I was working with. Was about 8/9pm, I decided to meditate whilst he read a book.
After a concentrating on each part of my body, from toes to forehead, and deep breathing, I felt like I was falling back. I recognised this as the feeling I follow to fall asleep, so I thought that I may aswell go to sleep, get up early tomorrow.
Instead, I kept falling and falling, I got dizzier and dizzier. I got worried and decided to break it off. I tried to get up, and I was moving megaslowly. I raised my arm, and it felt really heavy. I was trying to signal to my buddy that I was stuck.
I was in an imaginary version of the hotel room, I was looking around and trying to lift my arm - albeit slowly - whilst I could see my buddy reading his book, flipping the page.
When he did flip the page, it sounded so, so, SO loud! Like a plane wing screeching along the floor at full speed for a moment, echoing.
I nearly panicked, but calmed down. I remembered in movies and such how in hypnosis, they'd count backwards to wake the person up. I declared that counting backwards from 5 would wake me up. I counted backwards, I shot up in a sitting position gasping for air.
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This is a WARNING. After reading this up on the internet, it turns out I entered one of the deepest meditational states. These are difficult to attain and even moreso to wake up from and should not be attempted by the inexperienced.
If I had let myself panic, I might not of woken up. It's happened; people going into meditation and not waking up.
But, on the other hand, using this deepest state, you can travel back into previous lives and have out-of-body experiences - which is probably what I was having by looking around in my mind.