Hey Wizzy~
The problem (I suspect) is that you're using an addAction command in order to launch the missile.
AddAction commands will only execute a script LOCALLY and therefore, I suspect that is the issue that you are running into.
A simple work-around would be to have another script present (sitting dormant) that detects if a missile is launched and if so, launches the appropriate scripts to show the detonation. The only problem with this is, it will consume processor because it is sitting in a never-ending loop waiting for some variable to be reported as true. The good news is since you're launching a missile, you could put about a 5 second wait in there since I wouldn't expect anyone to lauch one that would be detonated that soon anyway.