I have had a few similar experiences. I have not been able to control this and it seems to last only a few seconds, like you have said maybe 30 seconds. This would happen to me very frequently when I was younger. It rarely happen to me now but I did see a scene briefly last night. I will usually see something in nature, like trees and fields. Sorry I cannot answer your questions, but I thought you might like to hear someone else who has experienced similar things.