Good plan, but this is the weak spot. You'd also want to do something like hand out remote kill switch access to citizens selected at random, who should not publicize this duty in any way. Alternatively, most if not all governments should have cross-country killswitch privileges. At any rate, the deployment of a killswitch in a single chain of command should not be considered sufficient.

Let's at least die with a little less embarrassment than "the AI bribed the killswitch operator."