On the screenshot you call a function without picking any missiles, so all of them are destroyed. I recommend not using function here (replace "call function" with the function actions). Or, if you want to use function, add a parameter and set it to UID of the missile. Then pick a missile by UID. I hope this makes sense to you.
Also, move the first action of event 4 just before the "destroy" action. It will get rid of every rock changing its angle every time.