Asakiyume mita

I don't remember but I think it must have lingered for a while, or maybe was recurring, with increased bubbling up of the gas from the lake. I read about people walking places on raised roads, and then would leave the road to cross a field, and suddenly would drop dead. They thought it would be safe, but they were wrong... so it must have continued on after the initial die-off, which had happened at night when people were asleep in their homes.