Progress in relation to ice crack creation

Using Maya I began to test ice creation. I began looking at some tutorials as I did in the summer. https://www.youtube.com/watch?v=QKYs1UXvTTQ by 3dtutorialzone is the main one that I was using. I first created a surface by manipulating a cube before using an EP Curve to extrude a crack through the middle of the surface. Following this, I created a locator and using the connection editor, I connected it to the crack and used a boolean difference. This should allow for the crack to be animate-able. 

 This is before the locator moves.

 This is after the locator moves.

 Strangely though, during the inbetween, the overall block vanishes and the crack appears alone.

    Just after this point, the cracked surface reappears as it did in the second photo. It is very strange but I plan to work on my animation as I figure this out. I will start animating the character now.