Here is a puzzle about Relativity that I am not able to solve; please help:

Imagine that Harry Potter is using his magical powers to test Relativity experimentally. He finds a very small room in a tower in Hogwarts, with two windows in opposing walls. He also finds a broom that is just a bit longer than the distance between the windows.

So, Professor Quirrell stands in the room and watches Harry fly through the room very fast. From Harry's point of view, the room became shorter. But from Professor Quirrell's point of view, it's Harry's broom that became shorter, and now it seems actually shorter than the distance between the windows.

As an experiment, Harry asks Professor Quirrell to quickly close and than open again both windows simultaneously when Harry is inside the room. From Professor Quirrel's point of view, it should be possible because the broom is shorter than the room. From Harry's point of view, it should be impossible because the broom is longer than the room.

What really happens is that "simultaneously" is also relative. This is how Professor Quirrell describes the event: When Harry was inside the room, both windows closed and opened simultaneously, keeping Harry trapped in the room for a short moment. This is how Harry describes it: Before he fully entered the room, the second window was closed and then opened; then he flew across; and then when he already partially left the room, the first window was closed and then opened behind his back. So for both observers the described events make sense.

Is this a correct explanation? (Seems so to me, but I am not sure.)

The problem is, Professor Quirrell, as usually, plays this game one level higher than Harry. Despite their agreement, he decides to close the both windows simultaneously and keep them closed. Let's suppose the windows and broom are magical, therefore almost indestructible. What exactly happens, microsecond after microsecond, from Professor Quirrell's point of view? (Until Harry's broom hits the second window, the situation should be exactly the same, right?) And what exactly happens from Harry's point of view?

Please post the answer rot13'd so that other people can make their guesses independently. I tried, but I'm giving up. I suspect that my inability to solve the second part means that I also got the first part wrong, but I don't see how exactly.