Final answer:
Sabrina's need to perform specific actions upon waking due to a belief that something bad will happen if she does not is indicative of Obsessive-Compulsive Disorder (OCD), not a sleep disorder like night terrors.
Step-by-step explanation:
The behaviors described in the question suggest that Sabrina is likely experiencing a form of Obsessive-Compulsive Disorder (OCD), which is a mental health disorder characterized by repetitive, unwanted thoughts (obsessions) and behavior (compulsions) that the person feels driven to perform. These symptoms are not related to a sleep disorder such as night terrors, as Sabrina performs these actions upon waking and believes something bad will happen if she does not complete them, which is indicative of OCD.
OCD can manifest in various forms, including the need for symmetry or exactness, forbidden thoughts, or the need to check things repeatedly. Sabrina's repetitive knocking and light switching are examples of compulsive behaviors meant to neutralize or prevent discomfort or some dreaded event, which is characteristic of OCD compulsions.