there is an option that you add on the event that says
switch on, and you name one and make it on. Then, add a new page to that event, and there are some options on the left side of the page, where it does say Switch, select the one you put ON on the other page, and that will make it.
When the movie ends, it will change page because of the switch and that new page is blank so it won't do anything else. That works to everything that you make with events...