Did the source imprison the smoke monster, but somehow receiving MIB allowed the monster to escape imprisonment? Did the source create the smoke monster once it received a human vehicle?
Related question is did the source want the smoke monster out in the world, or stuck in the earth? Does the source "want" anything?
What the hell is the source anyway?
Is it possible to let loose another smoke monster, e.g., a white smoke monster to fight the other one?