Explode is a method of blocks (BlockTableRecord) that you can call in VB.Net. Once you call it, you only get a collection of the objects in the block, the original block is still intact. You have to remove the original block, and place the exploded entities where you want them.
If you want to explode a block inside of a block, merely, move the entities from one BlockTableRecord(Nested Block) into the other BlockTableRecord(Parent Block). Explode doesn't even need to be run.
jvj