well its basically just rapid decompression except instead of a loud boom, frozen slushy soda goes all over the place, but it does travel parrallel to the lines of the bottle... meaning along the longest surface of the bottle. So if you hold it perpendicular to you, and poke the bottom, itll still go everywhere, but much less where ever you are.
I did this at work once, and it made such a mess, that i didnt even bother trying to clean it up... i made someone else do it. Took them 17min.