Unlicensed patient care assistants (PCAs) are often tasked with providing constant observation (CO) of patients with complex health behaviors. The unique demands of CO are poorly understood, making it challenging to design effective training. Four-component instructional design theory suggests the tasks associated with CO feature non-recurrent challenges, such that effective, simulation-based deliberate practice must reflect real-life variability. This study aimed to elucidate the variety of challenges PCAs encounter during CO of patients with complex health behaviors. We used a qualitative descriptive design and developed a preliminary framework to code interviews. The data collection framework was designed to support creating numerous realistic scenarios to support generalized and transferable learning. From our interviews with 16 participants, we identified 1,066 statements associated with variations in CO tasks. We grouped our findings by two domains, "patient factors" and "environmental contexts." Our results revealed many recurring and non-recurring challenges inherent in CO, requiring a range of skills to maintain patient and staff safety. Instructional design elements may include scenarios incorporating environment and resource assessment, cognitive feedback for non-recurrent tasks, novel methods of self-harm initiated by the patient, and incorporating interdisciplinary staff in which the learner must navigate a complex conversation. This study clarifies the task demands of CO and is useful as a task analysis to guide scenario development for simulation-based experiences. A less systematic approach would risk underrepresenting the difficulties inherent in the task, reinforcing a limited set of behaviors that may not generalize well to the non-recurrent challenges in CO.