Stella's rejection tantrum when her mother is still too busy to take care of her even when bringing her at a space security briefing reunion. Sarah takes it so bad she doesn't eat the next day and screws up during a crucial (underwater) extravehicular space activity simulation as a result.
Sarah not being able to touch or hug her daughter for a goodbye the day before the launch, having to stay in quarantine behind a glass window, with Stella not having much to say as this was yet another promise her mother could not fulfill. This prompts Sarah to sneakily leave her quarantine to see her daughter one last time and honor her promise.
Mike voicing out his concerns about leaving his wife and children behind to Sarah just before the launch.
