Leonid Toptunov

Leonid Toptunov is a young, newly qualified engineer on the night shift at Chernobyl's Reactor 4, still finding his feet in the job. Quiet and conscientious, he follows procedure and defers to his superiors, growing visibly uneasy as the reactor test he's asked to run stops behaving the way the manual says it should.

Robert Emms plays him as someone barely senior enough to be trusted with the controls, which makes every command from Dyatlov land differently — you watch a junior man's professional instincts fight against institutional pressure in real time. The performance is all held breath and darting eyes, and it turns a control-room shift into unbearable tension.