Possible Clues:

• Continually moving forward when leaving
• Not stopped
• When farewells are said to be in progress
• How I go up in the broken gong without a stop
• In progress (... first three letters)
• Like many investigations
• When to say goodbye, in the event?
• Give the geegee an onion and there's no stopping it
• Continuing to operate just after departing
• Continuing to exist or progress