Caleb was confused by how he felt. whenever she is there and he sees her, his heartbeat quickens. whenever he doesn’t see her, it seems lifeless. why is he so almost crazy to imagine why his heart is beating. After a few thousand thoughts he finally knew why. Because Paris is her world, Paris is the light, and Paris holds the key to her heart. that's why it manages to speed up his heartbeat. he was holding the key. he controls her heartbeat.