Still, this kind of thing isn't always applicable. If the seL4 kernel in question is on orbit, or running on a computer at an unknown location, or in a submarine, or in a drone in flight, the assassin can't in practice sit down at the console. And if it's running on something like the Secure Enclave chip in an iPhone, or a permissive action link, physical access may be impractically difficult regardless of who you kill.