Malfoy asked for a room where he wouldn’t be disturbed.
But Trelawney got in.
Actually Malfoy asked for a room to hide something in and so did Trelawney. That’s how she got in. Harry also asked to have a room to hide something in(his potions book). I think he was given the exact same room and didn’t realize it.I’m basing this on the description of the items in the room.
It was the same room, on page 526 it talks about him passing the vanishing cabinet when he is trying to hide his book. I think when he goes back for the book he’ll see it and realize what happened.
Any bets that there’s a Horcrux hidden there?