(It's Vex tech too. The SIVA is just a material used in the operation of the device. The tech is linked to Q's neural system and has programs inside it to keep it to the one basic function. Failure to meet the given function, of being an arm, will initiate a micro-self destruction. it doesnt explode but it would fall off and literally decay instantaneously. Plus, there's a Vex-originated A.I. installed in the arm that prevents the arm from being hacked with ease. Once control of the arm is lost, the micro-self destruction sequence is activated.) "Lets not forget reality cannot actually break. In this case he's more or less discovering new ways to explore or use reality and matter, not breaking it. Plus, this arm is mostly of Vex origin. 'Hacking' it with this era's technology would be harder than swimming through a blackhole after bathing in the core of an imploding star."