R0J0hound Using the method you described, it goes block by block in order when picking the next block to destroy, so I altered it a bit and instead of pick block.UID, it did a pick random instance of the block then assign block.UID to the target variable. This gives the effect of picking a random block each time as the target, but for some reason, whenever they are fired at, it stops after destroying 9 blocks. My assumption is that this is tied somehow to the initial logic creating the blocks as it is the only place I can find the number 9... could be pure coincidence, but after destroying 9 blocks, it stops spawning more enemies to shoot at the blocks... Here is a image of my events.
I can provide a capx, but everything is here in the sheet since it is all event driven...
<img src="https://dl.dropboxusercontent.com/u/10285716/BlockKillerEvents.png" border="0" />