This is a classic (but horrible) move in film: treating stalking like it's no big deal, or worse, romantic. Christian shows up out of nowhere all the time. It's part of his creepy persistence. Like the moment when he just happens to be in the neighborhood and decided to sho
at the hardware store where Ana works.
Or that time when sends him a message to firmly and unambiguous tells him she doesn't want to see him again in an email, and then he breaks into her house. He comes into her room and says "It's been nice knowing me, has it?" in a very menacing and not charming way. Needless to say, he scares her half to death. It's basically a jump scare for the audience, too. He's directly ignoring her when she says she doesn't want to have a relationship with him.
There's also that time that she mentions that Ana's going to Georgia to see her mom and Christian shows up at the exact same bar. How did he know which bar she's was at?!