It’s their strategy that screws them. They take too long to make a decision that the drivers question, then they change it and the drivers loose faith in their first and second opinion, and will next time there’s a call.

It’s more about pressure than airflow. You just need negative pressure inside the chamber, so gas escapes into your chamber through the cracks, and out the vent.

Saudis were happy to bankroll it to kill the main organisation platform behind the Arab Spring uprisings