Mass evacuation following company disturbance (9)
I believe the answer is:
commotion
'disturbance' is the definition.
(commotion is a kind of disturbance)
'mass evacuation following company' is the wordplay.
'mass evacuation' becomes 'motion' (I can't justify this - if you can you should give a lot more credence to this answer).
'following' is a charade indicator (letters next to each other).
'company' becomes 'com' (as in .com).
'motion' after 'com' is 'COMMOTION'.
Can you help me to learn more?
(Other definitions for commotion that I've seen before include "Row" , "Rumpus" , "Disorderly outburst" .)