A 19-month-old girl is brought to the emergency department after a seizure at home. Her mother says that her daughter became lethargic and flushed, then had a 2-minute tonic-clonic seizure that self-resolved. The patient has had 2 prior, similar presentations in the last 6 months, during which she has been admitted to the pediatric intensive care unit with extensive infectious, cardiac, and neurologic workups that were unrevealing; each time, she rapidly improved and returned to baseline within 24 hours of admission. On examination, her temperature is 38.3 C (100.9 F), blood pressure is 80/40 mm Hg, pulse is 162/min, and respirations are 26/min. The patient is arousable but falls back to sleep quickly. Her pupils are dilated, and she appears flushed. ECG reveals QRS prolongation. While evaluating the patient, the physician notices a prescription bottle for amitriptyline in the mother’s purse. The medical team is suspicious of a toxidrome and orders a urine sample for an extended urine toxicology screen. Her mother becomes distressed, stating, “Why do you need her urine for a seizure? I want to see a neurologist right now to evaluate her for epilepsy.” Which of the following is the most appropriate response?