Like sleep paralysis happens when we are about to enter rem stage so we don't act out our dreams, right?

I don't think that this is exactly the same. I think I got into sleep paralysis once with a particular technique that I was trying for lucid dreaming...but its a little bit different, I would say. There are many vivid reports of that phenomenon from people who have experienced it.

It happened to me lot of times. My mind was awake but body was paralized. For me 2 things work. Fokus on breathing then moving from my fingers wakes me up. Or I go back to sleep and continue with dreaming. In both ways I just need to breath and relax.