I’m not following everything 100%, but something stepped out at me.
If gas main work is being done in the street, and a Jewish person is responsible for turning off the gas there, wouldn’t that be causing him to do melacha on shabbos? (granted he is working in the street anyway, but this seems to be adding to it). After all, if the street valve is operated, and the internal house piping is sufficiently small, there would be less than a 5 second delay.