Create another Action, Under the "Loop" Within the Pick All Units and do (Actions), Under Unit Panel, named Damage Unit. You have Used this on your last trigger. Just change the (Triggering Unit) to (Picked Unit).
Then Paste your trigger for me to Correct anything wrong.
And That bj_wantDestroyGroup Destroys Leaks, which create lag later. Using it is a must THAT way.