Cutting an object in two in animation

Hi everyone,

Okay, so I am new to blender. I am used to modeling in solidworks, but for this animation, I wanted to try out blender.

The animation should demonstrate sample preparation inside a focused ion beam microscope.
The first steps of which are creating a ridge (made out of platinum)

[ATTACH=CONFIG]364978[/ATTACH]

And then create cuts on each side.
[ATTACH=CONFIG]364976[/ATTACH]

So far, I have been creating this using shape Keys (not sure if that is the best way) and animating their value.

The next step in the process will be a cut under an angle that cuts the “wall” free from the original object (see image below, the red area is the material to be cut away)


My question is now, how can I animate this cut? This wall (or lamella officially) should become a separate part.
What is the best approach for animation something like this?

something simular…

http://www.blenderartists.org/forum/showthread.php?353630-Dino

see post #6 for the animation…
notice the nice neet “Bite” at the end…

here’s a tutorial on use of the Boolean Modifier…