Board Thread:Role Play Discussion/@comment-25924729-20151108025945/@comment-5426254-20160312062335

He was on the second floor when he fought Lupin, so by the next post, he should be on the third floor.

Long story short: after he met Memories, he was dragged down to the first floor, before climbing all the way up to second floor to continue his rampage and fight Lupin, before moving upwards.