Let's dig a little deeper into James' character. First hypothesis: Let's say James is following Roan Gjoka, and sees that he is watching a woman, he may have called someone to find out who the woman is, and to get closer to Roan, he approaches Marina, offers her a drink, and tries to get some information out of her, then goes to confront Roan. Second hypothesis: James was hired by someone, probably Nikos, to try to keep her away from Andrew, he is following her when he sees that someone is watching Marina, he takes the opportunity to get closer, offers her a drink, talks to her and then he goes to confront Roan Gjoka, from then on we don't know if Marina and James had any reunion, after all this he follows Marina, when he arrives at the hotel where she is living he discovers that she is not there, pretending to be Marina's husband, he asks the receptionist to call her, and then maybe we have the call that Marina received while she was at the clinic with Andrew, the problem is because she left so quickly, she could have stayed with Andrew until the meeting ended.