You can launch a Set Snake outside of the outer bubble, then take the snake into the inner bubble and it is killed. The caveat is that anything in the inner bubble is destroyed.
Try it on test using a cave with one entrance and put the altar and random stuff in the bubble. You will have a ten second penalty while in the outer bubble. Strike right before entering the inner bubble, you will then notice the Set Snake is killed, but still destroys everything outside of the altar within the inner bubble.