This is how I do things it may or may not help.
I usually set my variables in an init box first either game logic or unit, set them false or true to give them a default.
in a triggers condition box place the testvar and set some text up so you know when it works.
create a second trigger set it 9,9,9 for the delay and type true in the condition box. In the on act box type testvar=true.
Nothing will happen until the second trigger reaches 9 seconds and it will set the testvar to true which will set off the second trigger.
You can have combinations of condition !(testvar) would check for a false variable and this and testvar would check the anyone present part of the trigger and the testvar would have to be true.
this a trigger I used yesterday and in may work for you
Place a trigger at the destination point and set it to anyone present,repeating and then in the condition box put
this && (player in thisList and !(alive badguy1))
it will activate it the player reaches this point and the badguy1 is dead.