A 52-year-old male with a history of rheumatoid arthritis presents for elective total knee replacement under general anesthesia. On pre-operative assessment, he has severe cervical spine limitation with a thyromental distance of 5 cm and an inter-incisor gap of 2 cm. Neck extension is severely restricted due to cervical ankylosis. After induction with propofol and succinylcholine, the anesthesiologist attempts direct laryngoscopy but visualizes only the epiglottis (Cormack-Lehane Grade 3). Bag-mask ventilation is adequate. What is the most appropriate next step according to the difficult airway algorithm?