That Mysterious/Scary Door at School

 I saw this meme recently, which got me thinking and sent me straight down nostalgia lane. Because this trap door in the ceiling looks awfully familar to me. My memory is not perfect, but it's very good and I am sure there was a door like this in my primary school, which both scared and fascinated me. Was it the hiding place of some demonic creature, a gateway to hell or another dimension? I think there is a scary story to be written about it. Maybe for Halloween. But does anyone has any idea about these doors in the ceiling that you can find in schools? My old primary school isn't that old, by the way, but it did have an old school feel, like it was carrying secrets from the past.