The fusion reactor (magnetic plasma containment, stellarator design) powering this android can feed some super-heated ultra-dense fusion material to the cannon through a chord. she can then pull the cannon and shoot, but after a few shots she has to wait for a recharge time, or the fusion chain reaction would be stopped due to having too little plasma in the containment. it is self sufficient though, so she can fully rechardge in a few hours by taking hydrogen from the water vapour in the air through condensation and subsequent electrolysis. can see her having an epic death by needing to strain the system with a lot of plasma, or simply due to needing to fire all the plasma she has in store