Actually if you make another event 'on animation 'walk' finished' and then drag that condition into the event that has 'on animation 'whatever' finished' you will get 2 triggers in the event. In the situation that more than 1 trigger appears in an event, each trigger is handled as though an or is between them.
on button 1 clicked
on button 2 clicked
Will result in the message "woohoo" appearing if you click button 1 or button 2.
However its kind of confusing because it reads like it should happen if they are clicked at the same time.