Here are the manuscripts. A German manuscript called Gladitoria group. It's currently in an Austrian museum.

Here is the main page
http://wiktenauer.com/wiki/Gladiatoria_%28MS_KK5013%29

And here is the specific drawing I am talking about
http://commons.wikimedia.org/wiki/File:Ms._KK5013_06r.jpg

The duelist clearly popped his pommel off and is throwing it.
This is strange to me because first off, it diminishes the sword by offsetting the balance, although a thrown pommel to an unarmored head might be dangerous, against a full armor suit I don't see the point of doing that. How did he get the pommel off?

Unless it was poorly peened, it shouldn't just pop off at your whim. They are on there pretty tightly. It usually takes a specialized tool to take them off that has much more force than a human hand trying to torque it off or pull it off.

This is just.. weird.

See this thread, and Nathan's links to others on the same topic.

http://www.myArmoury.com/talk/viewtopic.php?t=16868

Matt Easton has some views on this.
https://www.youtube.com/watch?v=IKIuKev_2ZA

It's become a 'thing' on Skallgrim's youtube.

End him rightly!

Also it's probably a joke page. They did that sometimes.