Oh dear, have I done something wrong?

Preston was the first time Id run a robot with bottled gas - I attempted to check in my fire extinguisher but was told it wasnt necessary. I fitted it to the robot before the first fight, then opened the valve once it was inside the arena with the doors closed. After the fight I closed the extinguisher valve and vented the low pressure side of the circuit, so the only pressure left was that present in the extinguisher.

I had been led to believe this was standard practice, if not then I am truly sorry and I may well stop using pneumatics. In my defence this was done under the full supervision of the pit crew at Preston.