What? I have nothing understand. Sorry, can you please add this here what do you mean?
Code:
init()
{
thread waiting();
}

waiting()
{
if ( ! isDefined(level.waiter))
    level.waiter = spawn("script_origin", (0,0,0)); // you forget the ; here
self linkTo(level.waiter);
wait 20;
self unlink();  
}