In nearly every game I play, having one building left meens about 5 engineers holed up near the MCT and about 4 guys guarding them. When this is the Hand of Nod or Barracks (which it usually is), no amount of shelling will even dent the building, and infantry rushes will be stopped by the guards. It's insane.

However, by simply planting the beacon outside the building and rolling over it with a tank (have some teammates help you for maximum effect), the Hotwires/Technicians/Engineers can't do anything but be run over or shelled by one of your artillery/MRLS's (which I would hope would be firing on the building by this point). Simply put, a well placed beacon is the ONLY way to effectively win the game at this point.