While on the Seaside Mutiny map, at the front of your base where the artillery platforms are, build the following. For the Chinese, build two Gatling Guns and a Bunker filled with Rocket Troopers. For U.S.A.. build two Patriots and a Fire Base with Rangers. For GLA, build two Stingers and a Tunnel Network. Capture the artillery platforms, then repeat the defense pattern on the sides as many times as possible. You can now build in the entire area without fear of enemy aircraft or land units.