Was It Worth It?

Spoilers


Ignoring the nonsensical plot and behavior of the future villains, what's up with the ending?

Emmy goes back to the future, resurrects King Ghidorah, builds it a mechanical third head and gives it a suit of armor, and some hooks and wires. That can't have been a quick task. It may have taken years? A decade? Who's to say? She then flies it back into the past and squares off against Godzilla. During their fight a huge portion of the city is destroyed before she can enact her plan, which is to pick Godzilla up, carry him a few miles out to sea, and drop him in the water. What??

They all seem to think it was a success. She flies out of the ocean and back to her future, and the Japanese cheer. Yay Emmy! But... Godzilla is just a few miles off shore. Why do they think he won't come back and wreck shit all over again?

Granted I wasn't paying intense attention, so if I missed some key plot point explaining why this works, then so be it.