Mary was surprised by the sudden change in environment. The corridor was no longer visible and neither was the light from it. She took a good look around before turning to the headmaster.

The teacher asked a question and people started answering. Mary thought about it. Her DADA textbook was not one she had skimmed through before coming here. She didn't want anything to muggle-ish, but knew very little about the wizarding world compared to most students.

Stepping closer to the teacher, as she knew she spoke very quietly, she finally decided on responding, "If you're not careful, it's very easy to trip or get stuck here. Especially during the night, as it is hard to see where you are going. If you do get stuck, this would be a good chance for someone our something to get you, because you would then be unable to to escape."