He is later hospitalized for radiation poisoning and Lyudmila goes to see him, lying to the doctors about being pregnant to get inside.
Lyudmila is, of course, referencing the events shown in the Chernobyl series.
Lyudmila shares with him her concern about the flames, but he dismisses it.
In the opening scene, firefighter Vasily Ignatenko is called to the power plant to put out a fire, not knowing that he’s about to be exposed to a devastating amount of radiation.