As the KNT are on their way to follow up a lead to discover whether Katze is in fact *gasp* A Woman, a red car with whip-em-up doors draws up before the very house they were looking for.
The driver looks up - and goes inside.
Professor Hume, a skinny old man in something like a Gandhi cloak, sees his visitor and cries "You!" (Interestingly, this was the teacher who knew the young Katze in male form.)
Looks can say more than words; and this look clearly says You Are Going To Die.