If the tank explodes, why do you assume the valve would remain stationary? Since the valve weighs less, wouldn't it be launched in the opposite direction from the tank at a much greater velocity, right into your back? I place my tanks horizontally, so they can hit the cars on both sides of me instead.Always place your tanks in your vehicle with the valves facing in such a direction that if your car is hit and a valve is broken the tank doesn't go through WHERE YOU ARE SITTING. I place mine in my trunk with the valves pointing forward so the tank is launched out the back of the car not into it.