In the above pic, I am well within a sword length of my opponent. This is probably the most dangerous possible place to stand. Fortunately, as you can see by the position of my leading foot, that I am in the process of moving off the line of attack. I can go either way. Jean (in the red armour) is focused on moving his entire attack towards me.
But instead of staying put, I brought left foot foward, moved my right foot to the left, my sword up and to my left, and in one beat (1/4 of a second), I ended up behind Jean. This requires some pretty fancy footwork, but certainly do-able even in full armour. The fencing world calls this an "en passant". I call it a gentle glide to the left forward corner as I ducked under his sword. It is safe providing I have cleverly protected myself the whole time with the flat of my own sword.
Once I get behind Jean, I want to keep behind him. The easiest way to stay behind is to shove his shoulder.
Lets change the camera angle to the back, and you can see how to properly shove a prepared and heavily armoured opponent. You can't just shove his shoulder with your hand...it wil probably just slide off, and you will be worse off. You have to prevent your opponent from moving clockwise to face you. So you are in a "situation".
As we look to the pic below, I have stepped a wee step forward to put my knee in behind Jean's right knee. A quick bend of my knee will unlock his leg. (which would be useful if I was pulling him towards me, but all it serves to do is to prevent him from stepping back with his right leg.
At the same time, I brought my elbow down into his tricep. And drove my left hip forward which we all know results in an explosion of power. You can also see a crush of my abs, and pecs along with the hip movement....this provides enough power to shift the Titanic
And thats the way they did it in the fifteenth century. I see no reason to not do it this way....grin! What Talhoffer fails to do is to explain how you can cleverly end up in this position. And here, in this series, I have just shown you.