If “Episode 3” saw AMC’s Humans pausing, really slowing down to focus on the domestic drama at the heart of its sci-fi-tinged story, “Episode 4” is the completely opposite, a thrilling and haunting hour of television that shows what Humans is truly all about. Up until this week, the show has largely been focused on small personal matters, looking at how technology, in the form of synths, influence the day-to-day lives of Laura, Pete, Dr.