My suggest is that you work with frames. On the first frame you put the "intor"-movieclip, and you start your script with "stop();", and that you give your script a timer or a button which will make him go to the next frame with "gotoAndStop(2);". Then you can place a videoloader script on the second frame. Than create an eventListener which will find out if the video is finished, en tell him to go to the third frame, which contains the credits.
Hope this will help you!