I was thinking that the Quartz Gun is a bit of a dangerous device. So far it seems that the writers are steadily raising the entropy levels of the show, instead of decreasing them, so having that canon could drive the writers to reach some point of no return, if not already reached, keep adding stuffs and stuffs, start even killing characters, and then BAAAM, firing the cannon to fix everything. The Scub Coral would be erased, everyone would come back to life and to his time and universe. Ao with her parents, Naru to the island, Elena wherever she came from. etc.
Or
vice versa the Scub Coral would be erased and everyone will live in this new earth (the our current one) not knowing each other anymore. In both ways they could avoid solving things in a sound way, given the short time left.
