In one scene, while Ryan and Elissa are kissing in his house, the girl in the basement hears them through a baby monitor, and decides to escape as a result. However, it doesn't make sense for Ryan to have set up the baby monitor so that only the girl in the basement can hear him, while he cannot hear her. It would make more sense for the two parts of the baby monitor to be switched so that he can hear her.
When Elisa's mother calls the house it diverts to her cell and appears as 'Mom' on the caller ID. When the officer calls the house and it diverts it should therefore appear as a cell phone number, but in fact it says 'Home'.