The thing with the troops is, you can think of them as a commando team moving in for an objective. Unless the troops got spotted or into a fight, the alarm won't go off. Not until they were entering the map room. Now if they modeled troops to start shooting stuff and what-not, THEN I see it valid for an alarm to be sounded. But as is, since they don't do anything except run, then I'd have to say no to base alarm for them, EXCEPT when they are 100 yards from the map room. Reason I give the 100 yard range is something like this; Think of it as the map room having sensors alerting to the presence of enemy troops. I would say guards, but guards would fire on them.