A 48-year-old male with a history of laryngeal papillomatosis and previous difficult intubation (Cormack–Lehane Grade 3) presents for elective laryngeal microsurgery. Awake fiberoptic intubation is planned. During the procedure, the scope is advanced into the larynx and the operator notes significant subglottic narrowing with papillomatous tissue. Which of the following is the MOST appropriate immediate action to optimize visualization and reduce the risk of tube malposition?