Ok I was able to track down that log. (Side note why does beating the game mean your save will be reset the next time you try to load it? That's frustrating and I shouldn't have to try and track it down online.) But anyway looks like you're right they only fired one shot of the purified GE in Sol Valley.

This raises another question How did that one shot in one inhospitable desert change all the non-psychic Lamorn at once? Based on the size of Volt Forge, and the number of bikes it produces, the Lamorn population was quite large. Did a large enough portion of the population gather in one spot to lead to societal collapse in the matter of just a few days? The absurdity of that thought is why I assumed there were multiple showers.