I was sleeping and my grandfather screamed of leg pain. He was fine when I went in there. But before that I had to get up first. The problem is that I was in REM sleep and he awoke me viciously in a jolting like way, my heart stopped for a few seconds, and it physically hurt my chest for a second. I'm afraid to go to sleep and him screaming again and awake me the same way, but this time have my heart completely stop. Is there any way to not have my heart stop upon someone screaming to wake me up?