Можешь еще поиграться с MGDDBG - он подскажет какие еще события возникают при попытке завершения AutoCAD:
QUIT
[Doc Mgr Event] : Document Lock Mode Will Change : Drawing2.dwg
Global Command Name : QUIT
Current Mode : NotLocked
My Current Mode : NotLocked
My New Mode : Write
[Doc Mgr Event] : Document Lock Mode Changed : Drawing2.dwg
Global Command Name : QUIT
Current Mode : Write
My Current Mode : NotLocked
My Previous Mode : Write
[Doc Event] : Command will Start : QUIT
[Doc Mgr Event] : Document Activation Changed : False
[Doc Mgr Event] : Document Activation Changed : True
[Doc Event] : Command Ended : QUIT
[Doc Mgr Event] : Document Lock Mode Will Change : Drawing2.dwg
Global Command Name : #QUIT
Current Mode : Write
My Current Mode : Write
My New Mode : NotLocked
[Doc Mgr Event] : Document Lock Mode Changed : Drawing2.dwg
Global Command Name : #QUIT
Current Mode : NotLocked
My Current Mode : Write
My Previous Mode : NotLocked