When you are down to that final nuclear fragment, the risk of a posterior capsule rupture is at its peak because there is no longer a physical barrier between your phaco tip and the bag. If the tip becomes occluded and then suddenly clears, the resulting post-occlusion surge can pull the floppy posterior capsule directly into the ultrasonic needle. In this case, that exact surge caused a break in the bag. To prevent this, I like to emphasize the Cataract Coach concept of holding your chopper in the safe position. By keeping the chopper horizontally behind the phaco tip and just in front of the posterior capsule, you create a physical internal shield. This smooth back surface of the chopper prevents the capsule from surging forward into the tip during those high-vacuum moments. If you need a refresher course about fluidics, see here.
