Well, that's why I asked for someone who knows programming. My experience was all back in the late 70s and early 80s with BASIC, I spent several years trying to learn C programming and decided it was almost as complicated as women, so beyond my comprehension. The sub's SIM and DAT files have references to the outer door animation, so the trigger programming is there, it just requires some programmer to tap into that animation subroutine to activate some kind of indicator.
Meantime Fish40, thanks for the tip - it works and is better than wasting torpedoes.