At the Red base, walk into the corner where there is a group of rocks. You will go through a secret teleporter find yourself under the bridge. Once there, look around for a trench. Get in it, and look for a little corner with a shotgun in it. Walk into that corner and you will find the secret room. There are rocket launchers, snipers, active camo, grenades, and overshields, along with a few pictures and a list of the beta testers.