Turning the gas on through the flipper arm wouldnt be seen as a good idea. Same goes for turning the robot over.

Have you considered the position of your dump valve? You mayaswell mount that next to your bottle by a hole in the back so it can be easily accessed.

"9.12 Dump Valve
All pneumatic systems must incorporate a pressure dump valve accessible from outside of the robot. This
dump valve shall quickly and reliably exhaust all gas downstream of the gas cylinder isolation (or remote
isolation) valve including systems with a maximum operating pressure of less than 50psi (3.4bar)."