This is how to do the middle sword disarm. Such a turn of the sword is done like this, which is the same as the first one, except that the grip is not the same.
The middle sword disarm works best when your opponents sword is more or less upright, such as in Posta Frontale. From the crossing of the swords as shown by the 3rd master, let go of the sword with your left hand. Spin the sword clockwise in a horizontal plane around its point of balance, so that the handle ends up on the outside.
Step through with your left foot, swinging your left hand up to the handle of your opponents sword between their hands. Keep the elbow in close to tie the action to your hip. This is the point shown.
As your weight sinks onto your left foot, keep your hips turning in a clockwise direction. With your left elbow close to your hip, let your forearm swing horizontally across your body, eventually pointing roughly behind you. This movement has the sensation of swatting the sword from your opponents hands.
As your left hand moves across the front of your body, keep the sword spinning. The point where your sword handle contacts your opponents blade wants to be above your left hand throughout this whole movement. This will snatch the sword from your opponents grip, throwing it behind you. It should sail through the air in a neatly upright position. You will be left in a single handed Posta di Fenestra in front of your astonished and weaponless opponent. You will be so close at this point that your sword tip will be right in their face. Use a quick flick of the hips to drive it into them.
You will see the same principles of this disarm used in the following plays.