PSA: If you see Chernobyl.S01E03.Open.Wide-.O.Earth.1080p.10bit... – the correct episode title is (no hyphen after "Wide"). The file is likely fine, just a scene naming glitch.
While the immediate disaster is being fought, scientist Ulana Khomyuk begins her investigation into the cause of the explosion. She interviews survivors like Toptunov and Akimov, discovering the "assumed impossibility" that the reactor exploded after the emergency shutdown button was pressed. Production Insights Chernobyl.S01E03.Open.Wide-.O.Earth.1080p.10bit...