Vehicles have multi-fused electrical systems to prevent short-circuits. Shorting any auxiliary connection in a vehicle would simple burn out the fuse or fusible link, it would not disable a vehicle or cause it to stop. Furthermore the cables in the engine compartment are multiple gauges heavier than shown in the monitor rig. Even if it were connected to the engines electrical system, the cables would overheat and break before they shorted the engine out.
Not only is detaching a gas line without a tool impossible, but achieving the correct stoichiometric ratio of gas to air to create an explosive ignition of the gas in a commercial kitchen would take hours, not seconds as shown.