He glanced at the map himself, watching the two of them in his office, drawing his finger up to Gryffindor Tower where Ginny was in the common room and Neville in his dormitory. Past that to the Astronomy Tower, where he recognized the names of two Fifth Year Ravenclaws who were indistinguishable from one another. To Hufflepuff, where Ernie MacMillan was pacing just outside their common room entrance.
"This map shows everyone at Hogwarts, where they are at this exact moment. So it shows your peers, your friends, the people you've spent the last seven years with. The number of times I looked at this map, watching my friends's names ..." he said, trailing off. He shook his head. "I just want you to take a look at everyone you know and understand that, if things start to change, these names will start disappearing."