The wedge zone has two marks; they divide the field horizontally and always force middle. Here, with the disc on the left half of the field, 1 forces middle and 2 puts a tight mark on the open side handler. Thus, neither of the handlers (O2 and O3) are easy options.
If the handler O2 gets the disc...
... it is now 2's job to mark and force middle, while 1 takes away the best handler option on the open side. The third handler (O3) is open but it won't be an easy throw.
(And, depending on where cutters are, the left-mid might pinch a little in order to discourage that option.)
Because the goal of the marks is to force throws up the middle, the shallow mid-mid (3) has the most active and important job -- ideally, he/she is able to shut down that space and get some Ds.
That shallow mid-mid takes away cutters coming under to receive throws up the middle...
... and the deeper mid-mid (4) defends the open space that results from that. The two mid-mids play off each other and communicate a lot.
(Reset positions.) The jobs of the left and right mids and deep are similar as in a 3-3-1 (cup) zone, including the left and right mids (5 and 6) defending against over the top throws like hammers.
A primary way for the offense handlers to bust this zone is...
... to run a give and go with the open side handler...
... getting past the marks, overwhelming one side ...
... and setting up more give and go and/or down field looks.
The deeper mid-mid or the mid on that side may pinch in/over to interfere with this, but the best way to avoid it is to never let that first throw off in the first place. So the handler marking by 1 and 2 is always critical.