Help with director mx!

Ok so i'm creating a game using director mx. A part of the game is the user has to select the numbers in ascending order in order to go to the next level. now i know how to make them disappear :

on mouseUp me
  sprite(8).visible = FALSE
end

But I don't know how to put a condition where in if the user doesn't click , 2 after 1, the game ends. could someone please help me. I'm a bit new to this :$