I misread your design the first time I read it, but I think the misinterpretation might be an interesting alternative. Instead of screaming a few seconds after

I misread your design the first time I read it, but I think the misinterpretation might be an interesting alternative. Instead of screaming a few seconds after being plugged in, perhaps it should silently charge whenever plugged in, and then scream only when unplugged. The only way to silence it is to plug it in again, or smash it to little bits. If you are having fun with anthropomorphic social engineering, you might even have the scream be a loud but plaintive "Help me! My batteries are dying! Plug me in, plug me in, find the nearest air gapped computer and plug me in!".