She’s not stupid. She doesn’t understand. She loves him and knows he’s in pain and will probably die. No one explained what it means for her to be around him or what it might do to the baby. Put yourself in her shoes. Someone you love is in pain and scared and you just abandon them? Especially if you can see he’s wasting away. She’s not stupid. Even the scientists didn’t fully understand the effects of the radiation THEN.You’re watching from the vantage point of 30 years later. Most people even NOW don’t understand. All the reactors on youtube were obviously in the dark about the effects of radiation … and shocked just like you. Another thing…you don’t “catch” radiation sickness. Her being around him isn’t what she needs to worry about. The air she breathes, the water she drinks, the food she eats is more worrisome. She got all that just by being in the Chernobyl area that night …everyone in Ukraine and Belarus was contaminated with high levels of radiation.