I appreciate his enthusiasm, but if this guy is trying to win this girl back, frankly, his technique is a little ham-handed. He really didn't put much thought into it. Threats *always* need to come from an anonymous psycho. Use a voice modulator from a pay phone for an extra creepy effect. Once she sees the threat is real you can come in as "the protector," promising to spend the night so you can save her from the bad guy. In the morning, after you've made passionate love all night, make a big production out of pretending to check the wiring, etc. in her car to be assured there are no bombs. Tell her to stand clear as you bravely start her car. After she heads off to work, you can get busy going through all her stuff, logging on to her computer, browsing her web history, and of course, monitoring her cell phone with the software you've put on it while she slept. As she unwittingly goes throughout her day thinking how lucky she is to have you back in her life, you are tracking her movements and activities and planning your next move accordingly, blocking potential suitors and conjuring threats to her physical safety.
Thus you are now able to create the insulated ecosystem of mental torture cycling into to dependency that you've been craving in your relationships. If this guy had just put a little thought into his plan he'd be sitting on the couch with her watching a movie, thinking about his next sinister move instead of wearing a green and white jumpsuit. I hope he's learned his lesson.