Related Clues:

• 'Later, alligator!'
• "Sayonara!"
• "Bye now!"
• 'Later, bitches!'
• 'TTFN'
• ''Bye now!''
• "Later, gator"
• "Take care of yourself!"
• "Hasta la vista"
• ''Gotta run!''
• 'It's been real!'
• Atomic Kitten's fond farewell
• Parting words, perhaps after the visit suggested by the starts of 20-, 38-/40- and 54-Across
• 'I gotta run!'
• Worrier's farewell