Post here your demos and examples with the source files.
Forum rules
Always post the games with a screenshot. The file must have the ged and data files (complete game source) Use the forum attachment to post the files. It is always better to use the first post to put the game files
Well seeing as you are using a global array instead of the actor*s (which would probably be a better method), you would have to set the subs of the array to some xy value not attainable by the actor. Just put aside a x value, in this case -999, and in destroy set it to that value. alien -> Destroy Actor -> Script Editor