Plug

So I had Plug and Pack (not present in this picture) be security robots who were also cold blooded murders, to keep peace in the ward they were assigned to keep watch of the people and if any one posed threat one of the robots would deal with it.
Pack would sever the person in half but Plug only shocked people, Plug being the smarter of the two could appoint certain shock levels to the target from 1 to 5, 5 being the deadliest.
Weird thing was I never pondered whether this would make the robot itself short circuit but the rods on the outside of Plug's headphones could be outlets for catching the extra electricity, maybe made out of steel or rubber.

Plug's "personality" was more duty orientated and passive not really in the mood to socialize or dwell on a conversation, probably more robotic then the other too, would probably display a reaction more when killing targets since it was fulfilling it's duty rather then Pack who liked hurting people just for the fun of it.