Professor:: "Try me"
Obviously, the professor knows something's up with the wardrobe, but Broadbent's line goes further than that.
The plot point reminded me of the ongoing debate about whether this or "Magician's Nephew" should be "Narnia book 1."
Personally, I'm glad they stuck with this story as the first.
Apparently, Lewis himself was vague on the issue. It IS clear, however, that he hadn't conceived of a sequel when he wrote this. He also considered both "Caspian" and "Dawn Treader" to be the "last" in the series. In that respect, it's hard to argue "Magician's Nephew" was ever meant to be the "first book in the series."
Think of the intro sequence of "Indiana Jones and the Last Crusade." No one's ever suggested cutting out River Phoenix's sequence and pasting it before "Raiders of the Lost Ark." Same here.
But again, fans and scholars differ on this issue.