Ulana Khomyuk

Ulana Khomyuk is a nuclear physicist from Minsk who hears about the Chernobyl explosion and starts asking questions nobody wants asked. She calculates the radiation numbers herself, refuses to accept official reassurances, and travels to the scene uninvited, driven by a scientist's need to know exactly what has gone wrong and why.

She's a composite figure representing the many scientists who pieced the truth together, and Watson plays her with a flat, unglamorous persistence that makes disbelief look like the most reasonable response in the room. There's no softening charm to her; she simply keeps stating facts until the men in charge run out of ways to ignore them.