dont know why they were all down there in the first place

I agree @aloha-creations. It's clear that this was a place parents warned their children to avoid. Perhaps, on their way back from practice this was the nearest place to seek shelter. That's what I'm thinking.

They are interviewing each person one by one to be sure the explanations line up. It's the rainy season in Thailand; therefore, this just may have been a last ditch effort to flee an unexpected deluge.

Best regards.

Peace.