Andrea's first thought as she listened to the dreaded phone ring was to wonder, could she get away with ignoring it? It was late, it would be perfectly understandable if she was asleep... Couldn't she let it go to voicemail and call back after she and Kyle had a chance to listen to the message and formulate a response?
She dismissed the idea instantly. It actually made a lot of sense for the Russians to be calling late. There was far less chance that she'd be in the middle of something where answering the burner phone would reveal its existence. In a way, calling this late was considerate, to secrecy if not her sleep schedule.
Her second thought, why might they be calling? Did they have news? Did they expect news?