The crack in the space and time that always looked over the island made temporary disappearance of the whole island's ecology.
To be honest, such a place was dangerous for students, but the Academy had grasped the timing of the 'switch', so for thousands of years, there had never been students who were trapped in the time and space crack.
Because of the invisible crack, many people associated this island with the famous Abyss and indeed, there was an Abyss entrance and exit on this island, which was why the island became such a strange one.
Not to mention that this Abyss' entrance and exit was one of the places that held the main seals, which means, if the Abyss' seals would ever be loose, the demons would come out of the entrance or exit on this island.
It was the same as Ainsley's Pandora Island because the Abyss entrance and exit there were also one of the main gates.