A 52-year-old man with severe ankylosing spondylitis presents for elective lumbar spine fusion. Clinical examination reveals complete cervical spine rigidity with severely limited mouth opening (interincisor distance 1.5 cm). Awake fiberoptic intubation is planned. After positioning the patient supine and applying topical anesthesia to the oropharynx and nasopharynx with 4% lidocaine spray, the patient develops sudden onset of severe airway anxiety and claustrophobia. What is the most appropriate immediate next step?