Stronghold without portal?

So I was just playing around and I found this stronghold. It seems too small, with a handful of rooms leading to dead ends for some reason. Then I copied the world in creative and blew up a few walls but I can’t seem to find anything at all. Am I doing something wrong or is there just no portal anywhere?

I’m playing Minecraft pocket edition and I have no idea how to find Stronghold with portal, I just wanna reach the end and see dragon.