Commentary
This play is connected to play 3 and play 4, because it shows different branch of the same action. It starts by besieging prima custodia with a krucke, while this time the defender reacts by cutting krucke to counter it. It may be krucke aimed at the opponent, or done as a schutzen in order to parry the opponent's sword. In both cases it will result in the same situation.
The second image show the correct followup - thrust low, under the opponent's sword, where is an opening. The tricky part is that the opponent is in the same situation, so he may do the same thing. But the attacker should be faster, as he has the initiative.
Third image warns us that there is always a danger - any fencer may decide to strike the head. But the defence is simple. The defender just continues with his slicing motion, that draws his sword up and defends the strike. He then even gets for a great position for a followup thrust, but that is not shown in the play.