When Senator Van Horn's and Broyles meet in the park, there is a man on a red bicycle passing by them twice in a eleven seconds. Same direction, left to right.
When the body of the character Randy is shown before and after combustion, his hands (thumbs in particular) have changed position.
Twice, Walter uses a Geiger counter. But he never removes the plastic cap protecting the sensing part when not in use. Hence, getting a radioactive reading on Astrid is not possible.
When speaking in Russian to his comatose brother, Timur refers to him sometimes as "Sashka", "Sashok" (diminutive of Aleksandr) and other times as "Lyokha", "Lionya" (diminutive of Aleksei). In fact, Timur actually cries "Aleksei!" zapping his brother for the first time. Despite being similar, Aleksandr and Aleksei are two quite different names in Russian and have different diminutive/pejorative forms.
When Broyles opens the dossier on brothers you can catch a glimpse of cosmonaut's full name: Aleks Ivanovich Vasiliev. "Aleks", being a modern short form of both Aleksei and Aleksandr, is not a "valid" name in Russia or Soviet Union. No parents could give their baby a name "Aleks" - in SU there were strict regulations/customs on this subject. Since Aleks is not a valid name, it couldn't form proper patronymic. "Aleksovich" (son of Aleks) sounds synthetic and just weird.